Microelectronic assemblies

ABSTRACT

Microelectronic assemblies, and related devices and methods, are disclosed herein. For example, in some embodiments, a microelectronic assembly may include: a first die having a first surface and an opposing second surface, first conductive contacts at the first surface of the first die, and second conductive contacts at the second surface of the first die; and a second die having a first surface and an opposing second surface, and first conductive contacts at the first surface of the second die; wherein the second conductive contacts of the first die are coupled to the first conductive contacts of the second die by interconnects, the second surface of the first die is between the first surface of the first die and the first surface of the second die, and a footprint of the first die is smaller than and contained within a footprint of the second die.

BACKGROUND

Integrated circuit dies are conventionally coupled to a packagesubstrate for mechanical stability and to facilitate connection to othercomponents, such as circuit boards. The interconnect pitch achievable byconventional substrates is constrained by manufacturing, materials, andthermal considerations, among others.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be readily understood by the following detaileddescription in conjunction with the accompanying drawings. To facilitatethis description, like reference numerals designate like structuralelements. Embodiments are illustrated by way of example, not by way oflimitation, in the figures of the accompanying drawings.

FIG. 1 is a side, cross-sectional view of an example microelectronicassembly, in accordance with various embodiments.

FIG. 2 is a bottom view of a die included in the microelectronicassembly of FIG. 1, in accordance with various embodiments.

FIGS. 3-11 are side, cross-sectional views of example microelectronicassemblies, in accordance with various embodiments.

FIGS. 12-16 are top views of example arrangements of multiple dies in amicroelectronic assembly, in accordance with various embodiments.

FIGS. 17A-17F are side, cross-sectional views of various stages in anexample process for manufacturing the microelectronic assembly of FIG.5, in accordance with various embodiments.

FIGS. 18A-18B are side, cross-sectional views of various stages inanother example process for manufacturing the microelectronic assemblyof FIG. 5, in accordance with various embodiments.

FIGS. 19A-19H are side, cross-sectional views of various stages inanother example process for manufacturing the microelectronic assemblyof FIG. 5, in accordance with various embodiments.

FIGS. 20-22 are side, cross-sectional views of example microelectronicassemblies, in accordance with various embodiments.

FIGS. 23A-23B are side, cross-sectional views of various stages in anexample process for manufacturing the microelectronic assembly of FIG.20, in accordance with various embodiments.

FIGS. 24A-24E are side, cross-sectional views of various stages in anexample process for manufacturing the microelectronic assembly of FIG.21, in accordance with various embodiments.

FIGS. 25A-25F are side, cross-sectional views of various stages in anexample process for manufacturing the microelectronic assembly of FIG.22, in accordance with various embodiments.

FIGS. 26A-26D are side, cross-sectional views of various stages inanother example process for manufacturing the microelectronic assemblyof FIG. 21, in accordance with various embodiments.

FIG. 27 is a side, cross-sectional view of an example microelectronicassembly, in accordance with various embodiments.

FIGS. 28-30 are side, cross-sectional views of example composite dies,in accordance with various embodiments.

FIGS. 31-34 are side, cross-sectional views of example microelectronicassemblies including example composite dies, in accordance with variousembodiments.

FIG. 35 is a side, cross-sectional view of another example compositedie, in accordance with various embodiments.

FIG. 36 is a side, cross-sectional view of an example microelectronicassembly including the composite die of FIG. 35, in accordance withvarious embodiments.

FIGS. 37A-37E are side, cross-sectional views of various stages in anexample process for manufacturing the microelectronic assembly of FIG.31, in accordance with various embodiments.

FIG. 38 is a top view of a wafer and dies that may be included in amicroelectronic assembly, in accordance with any of the embodimentsdisclosed herein.

FIG. 39 is a cross-sectional side view of an integrated circuit (IC)device that may be included in a microelectronic assembly, in accordancewith any of the embodiments disclosed herein.

FIG. 40 is a cross-sectional side view of an IC device assembly that mayinclude a microelectronic assembly, in accordance with any of theembodiments disclosed herein.

FIG. 41 is a block diagram of an example electrical device that mayinclude a microelectronic assembly, in accordance with any of theembodiments disclosed herein.

DETAILED DESCRIPTION

Microelectronic assemblies, and related devices and methods, aredisclosed herein. For example, in some embodiments, a microelectronicassembly may include: a first die having a first surface and an opposingsecond surface, first conductive contacts at the first surface of thefirst die, and second conductive contacts at the second surface of thefirst die; and a second die having a first surface and an opposingsecond surface, and first conductive contacts at the first surface ofthe second die; wherein the second conductive contacts of the first dieare coupled to the first conductive contacts of the second die byinterconnects, the second surface of the first die is between the firstsurface of the first die and the first surface of the second die, and afootprint of the first die is smaller than and contained within afootprint of the second die.

Communicating large numbers of signals between two or more dies in amulti-die integrated circuit (IC) package is challenging due to theincreasingly small size of such dies, thermal constraints, and powerdelivery constraints, among others. Various ones of the embodimentsdisclosed herein may help achieve reliable attachment of multiple ICdies at a lower cost, with improved power efficiency, with higherbandwidth, and/or with greater design flexibility, relative toconventional approaches. Various ones of the microelectronic assembliesdisclosed herein may exhibit better power delivery and signal speedwhile reducing the size of the package relative to conventionalapproaches. The microelectronic assemblies disclosed herein may beparticularly advantageous for small and low-profile applications incomputers, tablets, industrial robots, and consumer electronics (e.g.,wearable devices).

In the following detailed description, reference is made to theaccompanying drawings that form a part hereof wherein like numeralsdesignate like parts throughout, and in which is shown, by way ofillustration, embodiments that may be practiced. It is to be understoodthat other embodiments may be utilized and structural or logical changesmay be made without departing from the scope of the present disclosure.Therefore, the following detailed description is not to be taken in alimiting sense.

Various operations may be described as multiple discrete actions oroperations in turn, in a manner that is most helpful in understandingthe claimed subject matter. However, the order of description should notbe construed as to imply that these operations are necessarily orderdependent. In particular, these operations may not be performed in theorder of presentation. Operations described may be performed in adifferent order from the described embodiment. Various additionaloperations may be performed, and/or described operations may be omittedin additional embodiments.

For the purposes of the present disclosure, the phrase “A and/or B”means (A), (B), or (A and B). For the purposes of the presentdisclosure, the phrase “A, B, and/or C” means (A), (B), (C), (A and B),(A and C), (B and C), or (A, B, and C). The drawings are not necessarilyto scale. Although many of the drawings illustrate rectilinearstructures with flat walls and right-angle corners, this is simply forease of illustration, and actual devices made using these techniqueswill exhibit rounded corners, surface roughness, and other features.

The description uses the phrases “in an embodiment” or “in embodiments,”which may each refer to one or more of the same or differentembodiments. Furthermore, the terms “comprising,” “including,” “having,”and the like, as used with respect to embodiments of the presentdisclosure, are synonymous. As used herein, a “package” and an “ICpackage” are synonymous, as are a “die” and an “IC die.” The terms “top”and “bottom” may be used herein to explain various features of thedrawings, but these terms are simply for ease of discussion, and do notimply a desired or required orientation. As used herein, the term“insulating” means “electrically insulating,” unless otherwisespecified.

When used to describe a range of dimensions, the phrase “between X andY” represents a range that includes X and Y. For convenience, the phrase“FIG. 17” may be used to refer to the collection of drawings of FIGS.17A-17F, the phrase “FIG. 18” may be used to refer to the collection ofdrawings of FIGS. 18A-18B, etc. Although certain elements may bereferred to in the singular herein, such elements may include multiplesub-elements. For example, “an insulating material” may include one ormore insulating materials. As used herein, a “conductive contact” mayrefer to a portion of conductive material (e.g., metal) serving as anelectrical interface between different components; conductive contactsmay be recessed in, flush with, or extending away from a surface of acomponent, and may take any suitable form (e.g., a conductive pad orsocket, or portion of a conductive line or via).

FIG. 1 is a side, cross-sectional view of a microelectronic assembly100, in accordance with various embodiments. A number of elements areillustrated in FIG. 1 as included in the microelectronic assembly 100,but a number of these elements may not be present in a microelectronicassembly 100. For example, in various embodiments, the heat spreader131, the thermal interface material 129, the mold material 127, the die114-3, the die 114-4, the second-level interconnects 137, and/or thecircuit board 133 may not be included. Further, FIG. 1 illustrates anumber of elements that are omitted from subsequent drawings for ease ofillustration, but may be included in any of the microelectronicassemblies 100 disclosed herein. Examples of such elements include theheat spreader 131, the thermal interface material 129, the mold material127, the second-level interconnects 137, and/or the circuit board 133.Many of the elements of the microelectronic assembly 100 of FIG. 1 areincluded in other ones of the accompanying figures; the discussion ofthese elements is not repeated when discussing these figures, and any ofthese elements may take any of the forms disclosed herein. In someembodiments, individual ones of the microelectronic assemblies 100disclosed herein may serve as a system-in-package (SiP) in whichmultiple dies 114 having different functionality are included. In suchembodiments, the microelectronic assembly 100 may be referred to as anSiP.

The microelectronic assembly 100 may include a package substrate 102coupled to a die 114-1 by die-to-package substrate (DTPS) interconnects150-1. In particular, the top surface of the package substrate 102 mayinclude a set of conductive contacts 146, and the bottom surface of thedie 114-1 may include a set of conductive contacts 122; the conductivecontacts 122 at the bottom surface of the die 114-1 may be electricallyand mechanically coupled to the conductive contacts 146 at the topsurface of the package substrate 102 by the DTPS interconnects 150-1. Inthe embodiment of FIG. 1, the top surface of the package substrate 102includes a recess 108 in which the die 114-1 is at least partiallydisposed; the conductive contacts 146 to which the die 114-1 is coupledare located at the bottom of the recess 108. In other embodiments, thedie 114-1 may not be disposed in a recess (e.g., as discussed below withreference to FIGS. 9-11). Any of the conductive contacts disclosedherein (e.g., the conductive contacts 122, 124, 146, 140, and/or 135)may include bond pads, posts, or any other suitable conductive contact,for example.

The package substrate 102 may include an insulating material (e.g., adielectric material formed in multiple layers, as known in the art) andone or more conductive pathways through the dielectric material (e.g.,including conductive traces and/or conductive vias, as shown). In someembodiments, the insulating material of the package substrate 102 may bea dielectric material, such as an organic dielectric material, a fireretardant grade 4 material (FR-4), bismaleimide triazine (BT) resin,polyimide materials, glass reinforced epoxy matrix materials, or low-kand ultra low-k dielectric (e.g., carbon-doped dielectrics,fluorine-doped dielectrics, porous dielectrics, and organic polymericdielectrics). In particular, when the package substrate 102 is formedusing standard printed circuit board (PCB) processes, the packagesubstrate 102 may include FR-4, and the conductive pathways in thepackage substrate 102 may be formed by patterned sheets of copperseparated by build-up layers of the FR-4. The conductive pathways in thepackage substrate 102 may be bordered by liner materials, such asadhesion liners and/or barrier liners, as suitable.

In some embodiments, one or more of the conductive pathways in thepackage substrate 102 may extend between a conductive contact 146 at thetop surface of the package substrate 102 and a conductive contact 140 atthe bottom surface of the package substrate 102. In some embodiments,one or more of the conductive pathways in the package substrate 102 mayextend between a conductive contact 146 at the bottom of the recess 108and a conductive contact 140 at the bottom surface of the packagesubstrate 102. In some embodiments, one or more of the conductivepathways in the package substrate 102 may extend between differentconductive contacts 146 at the top surface of the package substrate 102(e.g., between a conductive contact 146 at the bottom of the recess 108and a different conductive contact 146 at the top surface of the packagesubstrate 102). In some embodiments, one or more of the conductivepathways in the package substrate 102 may extend between differentconductive contacts 140 at the bottom surface of the package substrate102.

The dies 114 disclosed herein may include an insulating material (e.g.,a dielectric material formed in multiple layers, as known in the art)and multiple conductive pathways formed through the insulating material.In some embodiments, the insulating material of a die 114 may include adielectric material, such as silicon dioxide, silicon nitride,oxynitride, polyimide materials, glass reinforced epoxy matrixmaterials, or a low-k or ultra low-k dielectric (e.g., carbon-dopeddielectrics, fluorine-doped dielectrics, porous dielectrics, organicpolymeric dielectrics, photo-imageable dielectrics, and/orbenzocyclobutene-based polymers). In some embodiments, the insulatingmaterial of a die 114 may include a semiconductor material, such assilicon, germanium, or a III-V material (e.g., gallium nitride), and oneor more additional materials. For example, an insulating material mayinclude silicon oxide or silicon nitride. The conductive pathways in adie 114 may include conductive traces and/or conductive vias, and mayconnect any of the conductive contacts in the die 114 in any suitablemanner (e.g., connecting multiple conductive contacts on a same surfaceor on different surfaces of the die 114). Example structures that may beincluded in the dies 114 disclosed herein are discussed below withreference to FIG. 39. The conductive pathways in the dies 114 may bebordered by liner materials, such as adhesion liners and/or barrierliners, as suitable.

In some embodiments, the die 114-1 may include conductive pathways toroute power, ground, and/or signals to/from some of the other dies 114included in the microelectronic assembly 100. For example, the die 114-1may include through-substrate vias (TSVs, including a conductivematerial via, such as a metal via, isolated from the surrounding siliconor other semiconductor material by a barrier oxide) or other conductivepathways through which power, ground, and/or signals may be transmittedbetween the package substrate 102 and one or more dies 114 “on top” ofthe die 114-1 (e.g., in the embodiment of FIG. 1, the die 114-2 and/orthe die 114-3). In some embodiments, the die 114-1 may includeconductive pathways to route power, ground, and/or signals betweendifferent ones of the dies 114 “on top” of the die 114-1 (e.g., in theembodiment of FIG. 1, the die 114-2 and the die 114-3). In someembodiments, the die 114-1 may be the source and/or destination ofsignals communicated between the die 114-1 and other dies 114 includedin the microelectronic assembly 100.

In some embodiments, the die 114-1 may not route power and/or ground tothe die 114-2; instead, the die 114-2 may couple directly to powerand/or ground lines in the package substrate 102. By allowing the die114-2 to couple directly to power and/or ground lines in the packagesubstrate 102, such power and/or ground lines need not be routed throughthe die 114-1, allowing the die 114-1 to be made smaller or to includemore active circuitry or signal pathways.

In some embodiments, the die 114-1 may only include conductive pathways,and may not contain active or passive circuitry. In other embodiments,the die 114-1 may include active or passive circuitry (e.g.,transistors, diodes, resistors, inductors, and capacitors, amongothers). In some embodiments, the die 114-1 may include one or moredevice layers including transistors (e.g., as discussed below withreference to FIG. 39. When the die 114-1 includes active circuitry,power and/or ground signals may be routed through the package substrate102 and to the die 114-1 through the conductive contacts 122 on thebottom surface of the die 114-1.

Although FIG. 1 illustrates a specific number and arrangement ofconductive pathways in the package of 102 and/or one or more of the dies114, these are simply illustrative, and any suitable number andarrangement may be used. The conductive pathways disclosed herein (e.g.,conductive traces and/or conductive vias) may be formed of anyappropriate conductive material, such as copper, silver, nickel, gold,aluminum, or other metals or alloys, for example.

In some embodiments, the package substrate 102 may be a lower densitymedium and the die 114-1 may be a higher density medium. As used herein,the term “lower density” and “higher density” are relative termsindicating that the conductive pathways (e.g., including conductivelines and conductive vias) in a lower density medium are larger and/orhave a greater pitch than the conductive pathways in a higher densitymedium. In some embodiments, a higher density medium may be manufacturedusing a modified semi-additive process or a semi-additive build-upprocess with advanced lithography (with small vertical interconnectfeatures formed by advanced laser or lithography processes), while alower density medium may be a PCB manufactured using a standard PCBprocess (e.g., a standard subtractive process using etch chemistry toremove areas of unwanted copper, and with coarse vertical interconnectfeatures formed by a standard laser process).

The microelectronic assembly 100 of FIG. 1 may also include a die 114-2.The die 114-2 may be electrically and mechanically coupled to thepackage substrate 102 by DTPS interconnects 150-2, and may beelectrically and mechanically coupled to the die 114-1 by die-to-die(DTD) interconnects 130-1. In particular, the top surface of the packagesubstrate 102 may include a set of conductive contacts 146, and thebottom surface of the die 114-2 may include a set of conductive contacts122; the conductive contacts 122 at the bottom surface of the die 114-1may be electrically and mechanically coupled to the conductive contacts146 at the top surface of the package substrate 102 by the DTPSinterconnects 150-2. Further, the top surface of the die 114-1 mayinclude a set of conductive contacts 124, and the bottom surface of thedie 114-2 may include a set of conductive contacts 124; the conductivecontacts 124 at the bottom surface of the die 114-2 may be electricallyand mechanically coupled to some of the conductive contacts 124 at thetop surface of the die 114-1 by the DTD interconnects 130-1. FIG. 2 is abottom view of the die 114-2 of the microelectronic assembly 100 of FIG.1, showing the “coarser” conductive contacts 122 and the “finer”conductive contacts 124. The die 114-2 of the microelectronic assembly100 may thus be a single-sided die (in the sense that the die 114-2 onlyhas conductive contacts 122/124 on a single surface), and may be amixed-pitch die (in the sense that the die 114-2 has sets of conductivecontacts 122/124 with different pitch). Although FIG. 2 illustrates theconductive contacts 122 and the conductive contacts 124 as each beingarranged in a rectangular array, this need not be the case, and theconductive contacts 122 and 124 may be arranged in any suitable pattern(e.g., hexagonal, rectangular, different arrangements between theconductive contacts 122 and 124, etc.). A die 114 that has DTPSinterconnects 150 and DTD interconnects 130 at the same surface may bereferred to as a mixed pitch die 114; more generally, a die 114 that hasinterconnects 130 of different pitches at a same surface may be referredto as a mixed pitch die 114.

The die 114-2 may extend over the die 114-1 by an overlap distance 191.In some embodiments, the overlap distance 191 may be between 0.5millimeters and 5 millimeters (e.g., between 0.75 millimeters and 2millimeters, or approximately 1 millimeter).

The microelectronic assembly 100 of FIG. 1 may also include a die 114-3.The die 114-3 may be electrically and mechanically coupled to the die114-1 by DTD interconnects 130-2. In particular, the bottom surface ofthe die 114-3 may include a set of conductive contacts 124 that areelectrically and mechanically coupled to some of the conductive contacts124 at the top surface of the die 114-1 by the DTD interconnects 130-2.In the embodiment of FIG. 1, the die 114-3 may be a single-sided,single-pitch die; in other embodiments, the die 114-3 may be adouble-sided (or “multi-level,” or “omni-directional”) die, andadditional components may be disposed on the top surface of the die114-3.

As discussed above, in the embodiment of FIG. 1, the die 114-1 mayprovide high density interconnect routing in a localized area of themicroelectronic assembly 100. In some embodiments, the presence of thedie 114-1 may support direct chip attach of fine-pitch semiconductordies (e.g., the dies 114-2 and 114-3) that cannot be attached entirelydirectly to the package substrate 102. In particular, as discussedabove, the die 114-1 may support trace widths and spacings that are notachievable in the package substrate 102. The proliferation of wearableand mobile electronics, as well as Internet of Things (IoT)applications, are driving reductions in the size of electronic systems,but limitations of the PCB manufacturing process and the mechanicalconsequences of thermal expansion during use have meant that chipshaving fine interconnect pitch cannot be directly mounted to a PCB.Various embodiments of the microelectronic assemblies 100 disclosedherein may be capable of supporting chips with high-densityinterconnects and chips with low-density interconnects withoutsacrificing performance or manufacturability.

The microelectronic assembly 100 of FIG. 1 may also include a die 114-4.The die 114-4 may be electrically and mechanically coupled to thepackage substrate 102 by DTPS interconnects 150-3. In particular, thebottom surface of the die 114-4 may include a set of conductive contacts122 that are electrically and mechanically coupled to some of theconductive contacts 146 at the top surface of the package substrate 102by the DTPS interconnects 150-3. In the embodiment of FIG. 1, the die114-4 may be a single-sided, single-pitch die; in other embodiments, thedie 114-4 may be a double-sided die, and additional components may bedisposed on the top surface of the die 114-4. Additional passivecomponents, such as surface-mount resistors, capacitors, and/orinductors, may be disposed on the top surface or the bottom surface ofthe package substrate 102, or embedded in the package substrate 102.

The microelectronic assembly 100 of FIG. 1 may also include a circuitboard 133. The package substrate 102 may be coupled to the circuit board133 by second-level interconnects 137 at the bottom surface of thepackage substrate 102. In particular, the package substrate 102 mayinclude conductive contacts 140 at its bottom surface, and the circuitboard 133 may include conductive contacts 135 at its top surface; thesecond-level interconnects 137 may electrically and mechanically couplethe conductive contacts 135 and the conductive contacts 140. Thesecond-level interconnects 137 illustrated in FIG. 1 are solder balls(e.g., for a ball grid array arrangement), but any suitable second-levelinterconnects 137 may be used (e.g., pins in a pin grid arrayarrangement or lands in a land grid array arrangement). The circuitboard 133 may be a motherboard, for example, and may have othercomponents attached to it (not shown). The circuit board 133 may includeconductive pathways and other conductive contacts (not shown) forrouting power, ground, and signals through the circuit board 133, asknown in the art. In some embodiments, the second-level interconnects137 may not couple the package substrate 102 to a circuit board 133, butmay instead couple the package substrate 102 to another IC package, aninterposer, or any other suitable component.

The microelectronic assembly 100 of FIG. 1 may also include a moldmaterial 127. The mold material 127 may extend around one or more of thedies 114 on the package substrate 102. In some embodiments, the moldmaterial 127 may extend above one or more of the dies 114 on the packagesubstrate 102. In some embodiments, the mold material 127 may extendbetween one or more of the dies 114 and the package substrate 102 aroundthe associated DTPS interconnects 150; in such embodiments, the moldmaterial 127 may serve as an underfill material. In some embodiments,the mold material 127 may extend between different ones of the dies 114around the associated DTD interconnects 130; in such embodiments, themold material 127 may serve as an underfill material. The mold material127 may include multiple different mold materials (e.g., an underfillmaterial, and a different overmold material). The mold material 127 maybe an insulating material, such as an appropriate epoxy material. Insome embodiments, the mold material 127 may include an underfillmaterial that is an epoxy flux that assists with soldering the dies114-1/114-2 to the package substrate 102 when forming the DTPSinterconnects 150-1 and 150-2, and then polymerizes and encapsulates theDTPS interconnects 150-1 and 150-2. The mold material 127 may beselected to have a coefficient of thermal expansion (CTE) that maymitigate or minimize the stress between the dies 114 and the packagesubstrate 102 arising from uneven thermal expansion in themicroelectronic assembly 100. In some embodiments, the CTE of the moldmaterial 127 may have a value that is intermediate to the CTE of thepackage substrate 102 (e.g., the CTE of the dielectric material of thepackage substrate 102) and a CTE of the dies 114.

The microelectronic assembly 100 of FIG. 1 may also include a thermalinterface material (TIM) 129. The TIM 129 may include a thermallyconductive material (e.g., metal particles) in a polymer or otherbinder. The TIM 129 may be a thermal interface material paste or athermally conductive epoxy (which may be a fluid when applied and mayharden upon curing, as known in the art). The TIM 129 may provide a pathfor heat generated by the dies 114 to readily flow to the heat spreader131, where it may be spread and/or dissipated. Some embodiments of themicroelectronic assembly 100 of FIG. 1 may include a sputtered back sidemetallization (not shown) across the mold material 127 and the dies 114;the TIM 129 (e.g., a solder TIM) may be disposed on this back sidemetallization.

The microelectronic assembly 100 of FIG. 1 may also include a heatspreader 131. The heat spreader 131 may be used to move heat away fromthe dies 114 (e.g., so that the heat may be more readily dissipated by aheat sink or other thermal management device). The heat spreader 131 mayinclude any suitable thermally conductive material (e.g., metal,appropriate ceramics, etc.), and may include any suitable features(e.g., fins). In some embodiments, the heat spreader 131 may be anintegrated heat spreader.

The DTPS interconnects 150 disclosed herein may take any suitable form.In some embodiments, a set of DTPS interconnects 150 may include solder(e.g., solder bumps or balls that are subject to a thermal reflow toform the DTPS interconnects 150). DTPS interconnects 150 that includesolder may include any appropriate solder material, such as lead/tin,tin/bismuth, eutectic tin/silver, ternary tin/silver/copper, eutectictin/copper, tin/nickel/copper, tin/bismuth/copper, tin/indium/copper,tin/zinc/indium/bismuth, or other alloys. In some embodiments, a set ofDTPS interconnects 150 may include an anisotropic conductive material,such as an anisotropic conductive film or an anisotropic conductivepaste. An anisotropic conductive material may include conductivematerials dispersed in a non-conductive material. In some embodiments,an anisotropic conductive material may include microscopic conductiveparticles embedded in a binder or a thermoset adhesive film (e.g., athermoset biphenyl-type epoxy resin, or an acrylic-based material). Insome embodiments, the conductive particles may include a polymer and/orone or more metals (e.g., nickel or gold). For example, the conductiveparticles may include nickel-coated gold or silver-coated copper that isin turn coated with a polymer. In another example, the conductiveparticles may include nickel. When an anisotropic conductive material isuncompressed, there may be no conductive pathway from one side of thematerial to the other. However, when the anisotropic conductive materialis adequately compressed (e.g., by conductive contacts on either side ofthe anisotropic conductive material), the conductive materials near theregion of compression may contact each other so as to form a conductivepathway from one side of the film to the other in the region ofcompression.

The DTD interconnects 130 disclosed herein may take any suitable form.The DTD interconnects 130 may have a finer pitch than the DTPSinterconnects 150 in a microelectronic assembly. In some embodiments,the dies 114 on either side of a set of DTD interconnects 130 may beunpackaged dies, and/or the DTD interconnects 130 may include smallconductive bumps or pillars (e.g., copper bumps or pillars) attached tothe conductive contacts 124 by solder. The DTD interconnects 130 mayhave too fine a pitch to couple to the package substrate 102 directly(e.g., to fine to serve as DTPS interconnects 150). In some embodiments,a set of DTD interconnects 130 may include solder. DTD interconnects 130that include solder may include any appropriate solder material, such asany of the materials discussed above. In some embodiments, a set of DTDinterconnects 130 may include an anisotropic conductive material, suchas any of the materials discussed above. In some embodiments, the DTDinterconnects 130 may be used as data transfer lanes, while the DTPSinterconnects 150 may be used for power and ground lines, among others.

In some embodiments, some or all of the DTD interconnects 130 in amicroelectronic assembly 100 may be metal-to-metal interconnects (e.g.,copper-to-copper interconnects, or plated interconnects). In suchembodiments, the conductive contacts 124 on either side of the DTDinterconnect 130 may be bonded together (e.g., under elevated pressureand/or temperature) without the use of intervening solder or ananisotropic conductive material. In some embodiments, one side of a DTDinterconnect 130 may include a metal pillar (e.g., a copper pillar), andthe other side of the DTD interconnect may include a metal contact(e.g., a copper contact) recessed in a dielectric. In some embodiments,a thin cap of solder may be used in a metal-to-metal interconnect toaccommodate planarity, and this solder may become an intermetalliccompound during processing. In some metal-to-metal interconnects thatutilize hybrid bonding, a dielectric material (e.g., silicon oxide,silicon nitride, silicon carbide, or an organic layer) may be presentbetween the metals bonded together (e.g., between copper pads or poststhat provide the associated conductive contacts 124). In someembodiments, a metal-to-metal interconnect (e.g., a copper-to-copperinterconnect) may include a noble metal (e.g., gold) or a metal whoseoxides are conductive (e.g., silver). In some embodiments, ametal-to-metal interconnect may include metal nanostructures (e.g.,nanorods) that may have a reduced melting point. Metal-to-metalinterconnects may be capable of reliably conducting a higher currentthan other types of interconnects; for example, some solderinterconnects may form brittle intermetallic compounds when currentflows, and the maximum current provided through such interconnects maybe constrained to mitigate mechanical failure.

In some embodiments, some or all of the DTD interconnects 130 in amicroelectronic assembly 100 may be solder interconnects that include asolder with a higher melting point than a solder included in some or allof the DTPS interconnects 150. For example, when the DTD interconnects130 in a microelectronic assembly 100 are formed before the DTPSinterconnects 150 are formed (e.g., as discussed below with reference toFIGS. 17A-17F), solder-based DTD interconnects 130 may use ahigher-temperature solder (e.g., with a melting point above 200 degreesCelsius), while the DTPS interconnects 150 may use a lower-temperaturesolder (e.g., with a melting point below 200 degrees Celsius). In someembodiments, a higher-temperature solder may include tin; tin and gold;or tin, silver, and copper (e.g., 96.5% tin, 3% silver, and 0.5%copper). In some embodiments, a lower-temperature solder may include tinand bismuth (e.g., eutectic tin bismuth) or tin, silver, and bismuth. Insome embodiments, a lower-temperature solder may include indium, indiumand tin, or gallium.

In the microelectronic assemblies 100 disclosed herein, some or all ofthe DTPS interconnects 150 may have a larger pitch than some or all ofthe DTD interconnects 130. DTD interconnects 130 may have a smallerpitch than DTPS interconnects 150 due to the greater similarity ofmaterials in the different dies 114 on either side of a set of DTDinterconnects 130 than between the die 114 and the package substrate 102on either side of a set of DTPS interconnects 150. In particular, thedifferences in the material composition of a die 114 and a packagesubstrate 102 may result in differential expansion and contraction ofthe die 114 and the package substrate 102 due to heat generated duringoperation (as well as the heat applied during various manufacturingoperations). To mitigate damage caused by this differential expansionand contraction (e.g., cracking, solder bridging, etc.), the DTPSinterconnects 150 may be formed larger and farther apart than DTDinterconnects 130, which may experience less thermal stress due to thegreater material similarity of the pair of dies 114 on either side ofthe DTD interconnects. In some embodiments, the DTPS interconnects 150disclosed herein may have a pitch between 80 microns and 300 microns,while the DTD interconnects 130 disclosed herein may have a pitchbetween 3 microns and 100 microns.

The elements of the microelectronic assembly 100 may have any suitabledimensions. Only a subset of the accompanying figures are labeled withreference numerals representing dimensions, but this is simply forclarity of illustration, and any of the microelectronic assemblies 100disclosed herein may have components having the dimensions discussedherein. For example, in some embodiments, the thickness 164 of thepackage substrate 102 may be between 0.1 millimeters and 1.4 millimeters(e.g., between 0.1 millimeters and 0.35 millimeters, between 0.25millimeters and 0.8 millimeters, or approximately 1 millimeter). In someembodiments, the recess 108 may have a depth 175 between 10 microns and200 microns (e.g., between 10 microns and 30 microns, between 30 micronsand 100 microns, between 60 microns and 80 microns, or approximately 75microns). In some embodiments, the depth 175 may be equal to a certainnumber of layers of the dielectric material in the package substrate102. For example, the depth 175 may be approximately equal to betweenone and five layers of the dielectric material in the package substrate102 (e.g., two or three layers of the dielectric material). In someembodiments, the depth 175 may be equal to the thickness of a solderresist material (not shown) on the top surface of the package substrate102.

In some embodiments, the distance 179 between the bottom surface of thedie 114-1 and the proximate top surface of the package substrate 102 (atthe bottom of the recess 108) may be less than the distance 177 betweenthe bottom surface of the die 114-2 and the proximate top surface of thepackage substrate 102. In some embodiments, the distance 179 may beapproximately the same as the distance 177. In some embodiments, thedistance 177 between the bottom surface of the die 114-2 and theproximate top surface of the package substrate 102 may be greater thanthe distance 193 between the bottom surface of the die 114-2 and theproximate top surface of the die 114-1. In other embodiments, thedistance 177 may be less than or equal to the distance 193.

In some embodiments, the top surface of the die 114-1 may extend higherthan the top surface of the package substrate 102, as illustrated inFIG. 1. In other embodiments, the top surface of the die 114-1 may besubstantially coplanar with the top surface of the package substrate102, or may be recessed below the top surface of the package substrate102. FIG. 3 illustrates an example of the former embodiment. Althoughvarious ones of the figures illustrate microelectronic assemblies 100having a single recess 108 in the package substrate 102, the thicknessof 102 may include multiple recesses 108 (e.g., having the same ordifferent dimensions, and each having a die 114 disposed therein), or norecesses 108. Examples of the former embodiments are discussed belowwith reference to FIGS. 7-8, and examples of the latter embodiments arediscussed below with reference to FIGS. 9-11. In some embodiments, arecess 108 may be located at the bottom surface of the package substrate102 (e.g., proximate to the conductive contacts 140), instead of or inaddition to a recess 108 at the top surface of the package substrate102.

In the embodiment of FIG. 1, a single die 114-2 is illustrated as“spanning” the package substrate 102 and the die 114-1. In someembodiments of the microelectronic assemblies 100 disclosed herein,multiple dies 114 may span the package substrate 102 and another die114. For example, FIG. 4 illustrates an embodiment in which two dies114-2 each have conductive contacts 122 and conductive contacts 124disposed at the bottom surfaces; the conductive contacts 122 of the dies114-2 are coupled to conductive contacts 146 at the top surface of thepackage substrate 102 via DTPS interconnects 150-2, and the conductivecontacts 124 of the dies 114-2 are coupled to conductive contacts 124 atthe top surface of the die 114 via DTD interconnects 130. In someembodiments, power and/or ground signals may be provided directly to thedies 114 of the microelectronic assembly 100 of FIG. 4 through thepackage substrate 102, and the die 114-1 may, among other things, routesignals between the dies 114-2.

In some embodiments, the die 114-1 may be arranged as a bridge betweenmultiple other dies 114, and may also have additional dies 114 disposedthereon. For example, FIG. 5 illustrates an embodiment in which two dies114-2 each have conductive contacts 122 and conductive contacts 124disposed at the bottom surfaces; the conductive contacts 122 of the dies114-2 are coupled to conductive contacts 146 at the top surface of thepackage substrate 102 via DTPS interconnects 150-2, and the conductivecontacts 124 of the dies 114-2 are coupled to conductive contacts 124 atthe top surface of the die 114 via DTD interconnects 130 (e.g., asdiscussed above with reference to FIG. 4). Additionally, a die 114-3 (ormultiple dies 114-3, not shown) is coupled to the die 114-1 byconductive contacts 124 on proximate surfaces of these dies 114 andintervening DTD interconnects 130-2 (e.g., as discussed above withreference to FIG. 1).

As noted above, any suitable number of the dies 114 in a microelectronicassembly 100 may be double-sided dies 114. For example, FIG. 6illustrates a microelectronic assembly 100 sharing a number of elementswith FIG. 1, but including a double-sided die 114-6. The die 114-6includes conductive contacts 122 and 124 at its bottom surface; theconductive contacts 122 at the bottom surface of the die 114-6 arecoupled to conductive contacts 146 at the top surface of the packagesubstrate 102 via DTPS interconnects 150-2, and the conductive contacts124 at the bottom surface of the die 114-6 are coupled to conductivecontacts 124 at the top surface of the die 114-1 via DTD interconnects130-1. The die 114-6 also includes conductive contacts 124 at its topsurface; these conductive contacts 124 are coupled to conductivecontacts 124 at the bottom surface of a die 114-7 by DTD interconnects130-3.

As noted above, a package substrate 102 may include one or more recesses108 in which dies 114 are at least partially disposed. For example, FIG.7 illustrates a microelectronic assembly 100 including a packagesubstrate 102 having two recesses: a recess 108-1 and a recess 108-2. Inthe embodiment of FIG. 7, the recess 108-1 is nested in the recess108-2, but in other embodiments, multiple recesses 108 need not benested. In FIG. 7, the die 114-1 is at least partially disposed in therecess 108-1, and the dies 114-6 and 114-3 are at least partiallydisposed in the recess 108-2. In the embodiment of FIG. 7, like theembodiment of FIG. 6, the die 114-6 includes conductive contacts 122 and124 at its bottom surface; the conductive contacts 122 at the bottomsurface of the die 114-6 are coupled to conductive contacts 146 at thetop surface of the package substrate 102 via DTPS interconnects 150-2,and the conductive contacts 124 at the bottom surface of the die 114-6are coupled to conductive contacts 124 at the top surface of the die114-1 via DTD interconnects 130-1. The die 114-6 also includesconductive contacts 124 at its top surface; these conductive contacts124 are coupled to conductive contacts 124 at the bottom surface of adie 114-7 by DTD interconnects 130-3. Further, the microelectronicassembly 100 of FIG. 7 includes a die 114-8 that spans the packagesubstrate 102 and the die 114-6. In particular, the die 114-8 includesconductive contacts 122 and 124 at its bottom surface; the conductivecontacts 122 at the bottom surface of the die 114-8 are coupled toconductive contacts 146 at the top surface of the package substrate 102via DTPS interconnects 150-3, and the conductive contacts 124 at thebottom surface of the die 114-8 are coupled to conductive contacts 124at the top surface of the die 114-6 via DTD interconnects 130-4.

In various ones of the microelectronic assemblies 100 disclosed herein,a single die 114 may bridge to other dies 114 from “below” (e.g., asdiscussed above with reference to FIGS. 4 and 5) or from “above.” Forexample, FIG. 8 illustrates a microelectronic assembly 100 similar tothe microelectronic assembly 100 of FIG. 7, but including twodouble-sided dies 114-9 and 114-10, as well as an additional die 114-11.The die 114-9 includes conductive contacts 122 and 124 at its bottomsurface; the conductive contacts 122 at the bottom surface of the die114-9 are coupled to conductive contacts 146 at the top surface of thepackage substrate 102 via DTPS interconnects 150-3, and the conductivecontacts 124 at the bottom surface of the die 114-9 are coupled toconductive contacts 124 at the top surface of the die 114-6 via DTDinterconnects 130-4. The die 114-6 includes conductive contacts 124 atits top surface; these conductive contacts 124 are coupled to conductivecontacts 124 at the bottom surface of a die 114-10 by DTD interconnects130-3. Further, the die 114-11 includes conductive contacts 124 at itsbottom surface; some of these conductive contacts 124 are coupled toconductive contacts 124 at the top surface of the die 114-9 by DTDinterconnects 130-6, and some of these conductive contacts 124 arecoupled to conductive contacts 124 at the top surface of the die 114-10by DTD interconnects 130-5. The die 114-11 may thus bridge the dies114-9 and 114-10.

As noted above, in some embodiments, the package substrate 102 may notinclude any recesses 108. For example, FIG. 9 illustrates an embodimenthaving dies 114 and a package substrate 102 mutually interconnected inthe manner discussed above with reference to FIG. 1, but in which thedie 114-1 is not disposed in a recess in the package substrate 102.Instead, the dies 114 are disposed above a planar portion of the topsurface of the package substrate 102. Any suitable ones of theembodiments disclosed herein that include recesses 108 may havecounterpart embodiments that do not include a recess 108. For example,FIG. 10 illustrates a microelectronic assembly 100 having dies 114 and apackage substrate 102 mutually interconnected in the manner discussedabove with reference to FIG. 4, but in which the die 114-1 is notdisposed in a recess in the package substrate 102.

Any of the arrangements of dies 114 illustrated in any of theaccompanying figures may be part of a repeating pattern in amicroelectronic assembly 100. For example, FIG. 11 illustrates a portionof a microelectronic assembly 100 in which an arrangement like the oneof FIG. 10 is repeated, with multiple dies 114-1 and multiple dies114-2. The dies 114-1 may bridge the adjacent dies 114-2. Moregenerally, the microelectronic assemblies 100 disclosed herein mayinclude any suitable arrangement of dies 114. FIGS. 12-16 are top viewsof example arrangements of multiple dies 114 in various microelectronicassemblies 100, in accordance with various embodiments. The packagesubstrate 102 is omitted from FIGS. 12-16; some or all of the dies 114in these arrangements may be at least partially disposed in a recess 108in a package substrate 102, or may not be disposed in a recess of apackage substrate 102. In the arrangements of FIGS. 12-16, the differentdies 114 may include any suitable circuitry. For example, in someembodiments, the die 114A may be an active or passive die, and the dies114B may include input/output circuitry, high bandwidth memory, and/orenhanced dynamic random access memory (EDRAM). The arrays of FIGS. 12-16are largely rectangular, but dies 114 may be positioned in any suitablearrangement (e.g., a non-rectangular array, such as a triangular array,a hexagonal array, etc.). Further, although dies 114 having rectangularfootprints are illustrated herein, the dies 114 may have any desiredfootprints (e.g., triangular, hexagonal, etc.), and such dies 114 may bearranged in any desired array (e.g., triangular, hexagonal, etc.).

FIG. 12 illustrates an arrangement in which a die 114A is disposed belowmultiple different dies 114B. The die 114A may be connected to a packagesubstrate 102 (not shown) in any of the manners disclosed herein withreference to the die 114-1, while the dies 114B may span the packagesubstrate 102 and the die 114A (e.g., in any of the manners disclosedherein with reference to the die 114-2). FIG. 12 also illustrates a die114C disposed on the die 114A (e.g., in the manner disclosed herein withreference to the die 114-3). In FIG. 12, the dies 114B “overlap” theedges and/or the corners of the die 114A, while the die 114C is whollyabove the die 114A. Placing dies 114B at least partially over thecorners of the die 114A may reduce routing congestion in the die 114Aand may improve utilization of the die 114A (e.g., in case the number ofinput/outputs needed between the die 114A and the dies 114B is not largeenough to require the full edge of the die 114A). In some embodiments,the die 114A may be disposed in a recess 108 in a package substrate 102.In some embodiments, the die 114A may be disposed in a recess 108 in apackage substrate 102, and the dies 114B may be disposed in one or morerecesses 108 in the package substrate 102. In some embodiments, none ofthe dies 114A or 114B may be disposed in recesses 108.

FIG. 13 illustrates an arrangement in which a die 114A is disposed belowmultiple different dies 114B. The die 114A may be connected to a packagesubstrate 102 (not shown) in any of the manners disclosed herein withreference to the die 114-1, while the dies 114B may span the packagesubstrate 102 and the die 114A (e.g., in any of the manners disclosedherein with reference to the die 114-2). FIG. 13 also illustrates dies114C disposed on the die 114A (e.g., in the manner disclosed herein withreference to the die 114-3). In FIG. 13, the dies 114B “overlap” theedges of the die 114A, while the dies 114C are wholly above the die114A. In some embodiments, the die 114A may be disposed in a recess 108in a package substrate 102. In some embodiments, the die 114A may bedisposed in a recess 108 in a package substrate 102, and the dies 114Bmay be disposed in one or more recesses 108 in the package substrate102. In some embodiments, none of the dies 114A or 114B may be disposedin recesses 108. In the embodiment of FIG. 13, the dies 114B and 114Cmay be arranged in a portion of a rectangular array. In someembodiments, two dies 114A may take the place of the single die 114Aillustrated in FIG. 13, and one or more dies 114C may “bridge” the twodies 114A (e.g., in the manner discussed below with reference to FIG.15).

FIG. 14 illustrates an arrangement in which a die 114A is disposed belowmultiple different dies 114B. The die 114A may be connected to a packagesubstrate 102 (not shown) in any of the manners disclosed herein withreference to the die 114-1, while the dies 114B may span the packagesubstrate 102 and the die 114A (e.g., in any of the manners disclosedherein with reference to the die 114-2). In FIG. 14, the dies 114B“overlap” the edges and/or the corners of the die 114A. In someembodiments, the die 114A may be disposed in a recess 108 in a packagesubstrate 102. In some embodiments, the die 114A may be disposed in arecess 108 in a package substrate 102, and the dies 114B may be disposedin one or more recesses 108 in the package substrate 102. In someembodiments, none of the dies 114A or 114B may be disposed in recesses108. In the embodiment of FIG. 14, the dies 114B may be arranged in aportion of a rectangular array.

FIG. 15 illustrates an arrangement in which multiple dies 114A aredisposed below multiple different dies 114B such that each die 114Abridges two or more horizontally or vertically adjacent dies 114B. Thedies 114A may be connected to a package substrate 102 (not shown) in anyof the manners disclosed herein with reference to the die 114-1, whilethe dies 114B may span the package substrate 102 and the die 114A (e.g.,in any of the manners disclosed herein with reference to the die 114-2).In FIG. 12, the dies 114B “overlap” the edges of the adjacent dies 114A.In some embodiments, the dies 114A may be disposed in one or morerecesses 108 in a package substrate 102. In some embodiments, the dies114A may be disposed in one or more recesses 108 in a package substrate102, and the dies 114B may be disposed in one or more recesses 108 inthe package substrate 102. In some embodiments, none of the dies 114A or114B may be disposed in recesses 108. In FIG. 15, the dies 114A and thedies 114B may be arranged in rectangular arrays.

FIG. 16 illustrates an arrangement in which multiple dies 114A aredisposed below multiple different dies 114B such that each die 114Abridges the four diagonally adjacent dies 114B. The dies 114A may beconnected to a package substrate 102 (not shown) in any of the mannersdisclosed herein with reference to the die 114-1, while the dies 114Bmay span the package substrate 102 and the die 114A (e.g., in any of themanners disclosed herein with reference to the die 114-2). In FIG. 12,the dies 114B “overlap” the corners of the adjacent dies 114A. In someembodiments, the dies 114A may be disposed in one or more recesses 108in a package substrate 102. In some embodiments, the dies 114A may bedisposed in one or more recesses 108 in a package substrate 102, and thedies 114B may be disposed in one or more recesses 108 in the packagesubstrate 102. In some embodiments, none of the dies 114A or 114B may bedisposed in recesses 108. In FIG. 16, the dies 114A and the dies 114Bmay be arranged in rectangular arrays.

Although FIGS. 12-16 were described above as “top” views of examplearrangements of multiple dies 114 in various microelectronic assemblies100, the arrangements of FIGS. 12-16 may also represent “bottom” views(i.e., arrangements in which the dies 114B are at least partiallybetween the dies 114A and the package substrate 102, and the dies 114Care between the dies 114A and the package substrate 102). In this“flipped” orientation, some or all of the dies 114 in FIGS. 12-16 may beat least partially disposed in a recess 108 in a package substrate 102,or may not be disposed in a recess of a package substrate 102, and thedifferent dies 114 may include any suitable circuitry (e.g., the dies114A may be active or passive dies, and the dies 114B may includeinput/output circuitry (e.g., in-package input/output circuitry orexternal input/output circuitry, such as Double Data Rate or PeripheralComponent Interconnect Express circuitry), high bandwidth memory, and/orEDRAM). In some embodiments, one or more of the dies 114 may includememory devices (e.g., random access memory), I/O drivers, high bandwidthmemory, accelerator circuitry (e.g., artificial intelligence acceleratorcircuitry), an application-specific integrated circuit (e.g., anartificial intelligence application-specific integrated circuit), afield programmable gate array, a processor core, a central processingunit, a graphics processing unit, or any suitable circuitry.

Any suitable techniques may be used to manufacture the microelectronicassemblies disclosed herein. For example, FIGS. 17A-17F are side,cross-sectional views of various stages in an example process formanufacturing the microelectronic assembly 100 of FIG. 5, in accordancewith various embodiments. Although the operations discussed below withreference to FIGS. 17A-17F (and others of the accompanying drawingsrepresenting manufacturing processes) are illustrated in a particularorder, these operations may be performed in any suitable order.Additionally, although particular assemblies are illustrated in FIGS.17A-17F (and others of the accompanying drawings representingmanufacturing processes), the operations discussed below with referenceto FIGS. 17A-17F may be used to form any suitable assemblies. In someembodiments, microelectronic assemblies 100 manufactured in accordancewith the process of FIGS. 17A-17F (e.g., any of the microelectronicassemblies 100 of FIGS. 1-11) may have DTPS interconnects 150-1 that aresolder interconnects, and DTD interconnects 130-1 and 130-2 that arenon-solder interconnects (e.g., metal-to-metal interconnects oranisotropic conductive material interconnects). In the embodiment ofFIGS. 17A-17F, the dies 114 may first be assembled into a “compositedie,” and then the composite die may be coupled to the package substrate102. This approach may allow for tighter tolerances in the formation ofthe DTD interconnects 130, and may be particularly desirable forrelatively small dies 114.

FIG. 17A illustrates an assembly 300 including a carrier 202 on whichthe dies 114-2 and 114-3 are disposed. The dies 114-2 and 114-3 are“upside down” on the carrier 202, in the sense that the conductivecontacts 122 and 124 of the dies 114 are facing away from the carrier202, and the conductive contacts 124 of the die 114-3 are facing awayfrom the carrier 202. The dies 114-2 and 114-3 may be secured to thecarrier using any suitable technique, such as a removable adhesive. Thecarrier 202 may include any suitable material for providing mechanicalstability during subsequent manufacturing operations (e.g., silicon,glass, ceramic, materials having a CTE similar to the dies 114 on thecarrier 202, etc.).

FIG. 17B illustrates an assembly 302 subsequent to coupling the die114-1 to the dies 114-2 and 114-3. In particular, the die 114-1 may bearranged “upside down” in the assembly 302 such that the conductivecontacts 124 of the die 114-1 may be coupled to the conductive contacts124 of the dies 114-2 (via DTD interconnects 130-1) and to theconductive contacts 124 of the die 114-3 (via DTD interconnects 130-2).Any suitable technique may be used to form the DTD interconnects 130 ofthe assembly 302, such as metal-to-metal attachment techniques, soldertechniques, or anisotropic conductive material techniques.

FIG. 17C illustrates an assembly 304 including a package substrate 203.The package substrate 203 may be structurally similar to the packagesubstrate 102 of FIG. 5, but may not include the recess 108 of thepackage substrate 102. In some embodiments, the package substrate 203may be manufactured using standard PCB manufacturing processes, and thusthe package substrate 203 may take the form of a PCB, as discussedabove. In some embodiments, the package substrate 203 may be a set ofredistribution layers formed on a panel carrier (not shown) bylaminating or spinning on a dielectric material, and creating conductivevias and lines by laser drilling and plating. Any method known in theart for fabrication of the package substrate 203 may be used, and forthe sake of brevity, such methods will not be discussed in furtherdetail herein.

FIG. 17D illustrates an assembly 306 subsequent to forming a recess 108in the package substrate 203 (FIG. 17C) to form the package substrate102. The recess 108 may have a bottom surface at which conductivecontacts 146 are exposed. Any suitable technique may be used to form therecess 108. For example, in some embodiments, the recess 108 may belaser-drilled down to a planar metal stop in the package substrate 203(not shown); once the metal stop is reached, the metal stop may beremoved to expose the conductive contacts 146 at the bottom of therecess 108. In some embodiments, the recess 108 may be formed by amechanical drill.

FIG. 17E illustrates an assembly 308 subsequent to “flipping” theassembly 302 (FIG. 17B) and bringing the dies 114-1 and 114-2 intoalignment with the package substrate 102 (FIG. 17D) so that theconductive contacts 122 on the dies 114-1 and 114-2 are aligned withtheir respective conductive contacts 146 on the top surface of thepackage substrate 102.

FIG. 17F illustrates an assembly 310 subsequent to forming DTPSinterconnects 150 between the dies 114-1/114-2 and the package substrate102 of the assembly 308 (FIG. 17E), then removing the carrier. The DTPSinterconnects 150 may take any of the forms disclosed herein (e.g.,solder interconnects, or anisotropic conductive material interconnects),and any suitable techniques may be used to form the DTPS interconnects150 (e.g., a mass reflow process or a thermal compression bondingprocess). The assembly 310 may take the form of the microelectronicassembly 100 of FIG. 5. Further operations may be performed as suitable(e.g., providing a mold material 127, providing a TIM 129, providing aheat spreader 131, attaching additional dies 114 to the packagesubstrate 102, etc.).

FIGS. 18A-18B are side, cross-sectional views of various stages inanother example process for manufacturing the microelectronic assembly100 of FIG. 5, in accordance with various embodiments. In someembodiments, microelectronic assemblies 100 manufactured in accordancewith the process of FIGS. 18A-18B (e.g., any of the microelectronicassemblies 100 of FIGS. 1-11) may have DTPS interconnects 150-1 that aresolder interconnects, and DTD interconnects 130-1 and 130-2 that arealso solder interconnects. In the embodiment of FIGS. 18A-18B, the die114-1 may be coupled to the package substrate 102, and then theremaining dies 114 may be attached. This approach may accommodate thetolerance and warpage of the package substrate 102, and may beparticularly desirable for relatively larger dies 114. The process ofFIGS. 17A-17F may advantageously be more compatible with non-solder DTDinterconnects 130, while the process of FIGS. 18A-18B may advantageouslyinvolve simpler handling of the dies 114.

FIG. 18A illustrates an assembly 312 subsequent to coupling the die114-1 to the package substrate 102. In particular, the die 114-1 may bepositioned in the recess 108, and conductive contacts 122 at the bottomsurface of the die 114-1 may be coupled to conductive contacts 146 atthe top surface of the package substrate 102 by DTPS interconnects150-1. The DTPS interconnects 150-1 may take the form of any of theembodiments disclosed herein, such as solder interconnects oranisotropic conductive material interconnects. The package substrate 102may be formed in accordance with any of the techniques discussed abovewith reference to FIGS. 17C-17D.

FIG. 18B illustrates an assembly 314 subsequent to coupling the dies114-2 and 114-3 to the assembly 312 (FIG. 18A). In particular, theconductive contacts 124 of the die 114-1 may be coupled to theconductive contacts 124 of the dies 114-2 (via DTD interconnects 130-1)and to the conductive contacts 124 of the die 114-3 (via DTDinterconnects 130-2). Further, the conductive contacts 122 of the dies114-2 may be coupled to conductive contacts 146 at the top surface ofthe package substrate 102 via DTPS interconnects 150-2. Any suitabletechnique may be used to form the DTD interconnects 130-1 and 130-2, andthe DTPS interconnects 150-2, of the assembly 314, such as soldertechniques or anisotropic conductive material techniques. For example,the DTPS interconnects 150-2 and the DTD interconnects 130-1/130-2 maybe solder interconnects. The assembly 314 may take the form of themicroelectronic assembly 100 of FIG. 5. Further operations may beperformed as suitable (e.g., providing a mold material 127, providing aTIM 129, providing a heat spreader 131, attaching additional dies 114 tothe package substrate 102, etc.).

FIGS. 19A-19H are side, cross-sectional views of various stages inanother example process for manufacturing the microelectronic assembly100 of FIG. 5, in accordance with various embodiments. In someembodiments, microelectronic assemblies 100 manufactured in accordancewith the process of FIGS. 19A-19H (e.g., any of the microelectronicassemblies 100 of FIGS. 1-11) may have DTPS interconnects 150-1 that arenon-solder interconnects (e.g., anisotropic conductive materialinterconnects), and DTD interconnects 130-1 and 130-2 that are solderinterconnects.

FIG. 19A illustrates an assembly 315 including a package substrateportion 113 on a carrier 202. The package substrate portion 113 may bethe “top” portion of the package substrate 102, as discussed furtherbelow, and may include conductive contacts 146 at the surface of thepackage substrate portion 113 facing away from the carrier 202. Thecarrier 202 may take any of the forms disclosed herein. The packagesubstrate portion 113 may be formed on the carrier 202 using anysuitable technique, such as a redistribution layer technique.

FIG. 19B illustrates an assembly 316 subsequent to forming a cavity 111in the package substrate portion 113 of the assembly 315 (FIG. 19A). Thecavity 111 may be formed using any of the techniques discussed abovewith reference to the recess 108 of FIG. 17D, for example. As discussedin further detail below, the cavity 111 may correspond to the recess108.

FIG. 19C illustrates an assembly 318 subsequent to positioning the die114-1 in the cavity 111 of the assembly 316 (FIG. 19B). The die 114-1may be positioned in the cavity 111 so that the conductive contacts 122face the carrier 202 and the conductive contacts 124 face away from thecarrier 202. In some embodiments, a pick-and-place machine may be usedto position the die 114-1 in the cavity 111 on the carrier 202.

FIG. 19D illustrates an assembly 320 subsequent to coupling the dies114-2 and 114-3 to the assembly 318 (FIG. 19C), and providing a moldmaterial 127 around the dies 114. In particular, the conductive contacts124 of the die 114-1 may be coupled to the conductive contacts 124 ofthe dies 114-2 (via DTD interconnects 130-1) and to the conductivecontacts 124 of the die 114-3 (via DTD interconnects 130-2). Further,the conductive contacts 122 of the dies 114-2 may be coupled toconductive contacts 146 at the top surface of the package substrate 102via DTPS interconnects 150-2. Any suitable technique may be used to formthe DTD interconnects 130-1 and 130-2, and the DTPS interconnects 150-2,of the assembly 314, such as solder techniques or anisotropic conductivematerial techniques. For example, the DTPS interconnects 150-2 and theDTD interconnects 130-1/130-2 may be solder interconnects. The moldmaterial 127 may take any of the forms disclosed herein, and may providemechanical support for further manufacturing operations.

FIG. 19E illustrates an assembly 321 subsequent to attaching anothercarrier 204 to the top surface of the assembly 320 (FIG. 19D). Thecarrier 204 may take the form of any of the embodiments of the carrier202 disclosed herein.

FIG. 19F illustrates an assembly 322 subsequent to removing the carrier202 from the assembly 321 (FIG. 19E) and flipping the result so that thepackage substrate portion 113 and the conductive contacts 122 of the die114-1 are exposed.

FIG. 19G illustrates an assembly 324 subsequent to forming an additionalpackage substrate portion 115 on the package substrate portion 113 ofthe assembly 322 (FIG. 19F) to form the package substrate 102. Anysuitable technique may be used to form the package substrate portion113, including any of the techniques discussed above with reference toFIG. 19A, a bumpless build-up layer technique, a carrier-basedpanel-level coreless package substrate manufacturing technique, or anembedded panel-level bonding technique. In some embodiments, forming thepackage substrate portion 115 may include plating the conductivecontacts 122 of the die 114-1 with a metal or other conductive materialas part of forming the proximate conductive contacts 146 of the packagesubstrate 102; consequently, the DTPS interconnects 150-1 between thedie 114-1 and the package substrate 102 may be plated interconnects.

FIG. 19H illustrates an assembly 325 subsequent to removing the carrier204 from the assembly 324 (FIG. 19G) and flipping the result. Theassembly 325 may take the form of the microelectronic assembly 100 ofFIG. 5. Further operations may be performed as suitable (e.g., providinga TIM 129, providing a heat spreader 131, attaching additional dies 114to the package substrate 102, etc.).

In the microelectronic assemblies 100 discussed above with reference toFIGS. 1-11, the die 114-1 is coupled directly to at least one die 114-2without any intervening portion of the package substrate 102. In otherembodiments of the microelectronic assemblies 100 disclosed herein, aportion of the package substrate 102 may be disposed between an embeddeddie 114-1 and a die 114-2. FIGS. 20-22 are side, cross-sectional viewsof example microelectronic assemblies 100 including such a feature, inaccordance with various embodiments. In particular, FIGS. 20-22illustrate arrangements of dies 114-1, 114-2, 114-3, and 114-4 that aresimilar to the arrangement illustrated in FIG. 1, but that furtherinclude a package substrate portion 148 between the top surface of thedie 114-1 and the top surface of the package substrate 102. The dies114-2, 114-3, and 114-4 may all be coupled to this package substrateportion 148. For example, the die 114-1 may include conductive contacts122 at its bottom surface that couple to conductive contacts 146 of thepackage substrate 102 via DTPS interconnects 150-1, and the die 114-1may include conductive contacts 122 at its top surface that couple toconductive contacts 146 of the package substrate 102 (in the packagesubstrate portion 148) via DTPS interconnects 150-4.

In some embodiments, the package substrate portion 148 may include oneor more areas 149 with higher conductive pathway density (e.g., theareas in which the footprint of the die 114-2 overlaps with thefootprint of the die 114-1 and the package substrate portion 148includes conductive pathways between the die 114-2 and the die 114-1, orthe areas in which the footprint of the die 114-3 overlaps of thefootprint of the die 114-1 and the package substrate portion 148includes conductive pathways between the die 114-3 and the die 114-1).Thus, the die 114-2 may be a mixed-pitch die including larger-pitchconductive contacts 122A and smaller-pitch conductive contacts 122B; thelarger-pitch conductive contacts 122A may couple (through some of theDTPS interconnects 150-2) to conductive contacts 146 on the top surfaceof the package substrate 102 (that themselves couple to conductivepathways through the bulk of the package substrate 102), and thesmaller-pitch conductive contacts 122B may couple (through some of theDTPS interconnects 150-2) to conductive contacts 146 on the top surfaceof the package substrate 102 (that themselves couple to conductivepathways through the package substrate portion 148 and to the die114-1). Similarly, the pitch of the conductive contacts 122 at thebottom surface of the die 114-3 (which may be coupled via the DTPSinterconnects 150-5 to dense conductive pathways through the packagesubstrate portion 148 to the die 114-1) may be smaller than the pitch ofthe conductive contacts 122 at the bottom surface of the die 114-4(which may be coupled via the DTPS interconnects 150-3 to less denseconductive pathways through the package substrate 102). The packagesubstrate 102 may also include a portion 151 adjacent to the die 114-1,and a portion 153 below the die 114-1.

FIG. 20 illustrates an embodiment in which the conductive pathways inthe package substrate 102 are provided by conductive lines and vias, asknown in the art. In other embodiments, the package substrate 102 mayinclude conductive pillars (e.g., copper pillars) and other structures.For example, FIG. 21 illustrates a microelectronic assembly 100 similarto that of FIG. 20, but in which the package substrate portion 151includes a plurality of conductive pillars 134 disposed around the die114-1. The conductive pillars 134 may be substantially surrounded by amold material 132, which may take the form of any of the mold materials127 disclosed herein. The conductive pillars 134 may be part ofconductive pathways between the package substrate portion 148 and thepackage substrate portion 153. Non-conductive pillars (e.g., pillarsformed of a permanent resist or a dielectric) may be used instead of orin addition to conductive pillars 134 in any suitable ones of theembodiments disclosed herein.

The conductive pillars 134 may be formed of any suitable conductivematerial, such as a metal. In some embodiments, the conductive pillars134 may include copper. The conductive pillars 134 may have any suitabledimensions. For example, in some embodiments, an individual conductivepillar 134 may have an aspect ratio (height:diameter) between 1:1 and4:1 (e.g., between 1:1 and 3:1). In some embodiments, an individualconductive pillar 134 may have a diameter between 10 microns and 300microns. In some embodiments, an individual conductive pillar 134 mayhave a diameter between 50 microns and 400 microns.

In some embodiments in which a package substrate 102 includes aplurality of conductive pillars 134, the package substrate portion 151may also include a placement ring. For example, FIG. 22 illustrates anembodiment of the microelectronic assembly 100 similar to that of FIG.21, but further including a placement ring 136. The placement ring 136may be formed of any suitable material (e.g., a plated copper featurewith a coating of an organic material, stainless steel, or anon-conductive material, such as glass, sapphire, polyimide, or epoxywith silica), and may be shaped so as to fit closely around the die114-1. In some embodiments, the placement ring 136 may have slanted orstraight walls to help guide the die 114-1 into position. Thus, theshape of the placement ring 136 may complement the shape of thefootprint of the die 114-1, and the placement ring 136 may help to alignthe die 114-1 during manufacture, as discussed further below.

Microelectronic assemblies 100 including embedded dies 114 may includeany suitable arrangement of dies 114. For example, any of thearrangements illustrated in FIGS. 12-16 may be implemented with the die114A embedded in a package substrate, with the dies 114A and 114Bembedded in a package substrate 102, or with the dies 114A, 1146, and114C embedded in a package substrate 102. Additionally, any of thearrangements illustrated in FIGS. 1-11 may be implemented with the die114-1 (and optionally more of the dies 114) embedded in a packagesubstrate 102, in accordance with any of the embodiments of FIGS. 20-22.

Any suitable techniques may be used to manufacture microelectronicassemblies 100 having an embedded die 114-1 (e.g., having a packagesubstrate portion 148 between the die 114-1 and the die 114-2). Forexample, FIGS. 23A-23B are side, cross-sectional views of various stagesin an example process for manufacturing the microelectronic assembly 100of FIG. 20, in accordance with various embodiments. In some embodiments,microelectronic assemblies 100 manufactured in accordance with theprocess of FIGS. 23A-23B may have DTPS interconnects 150-1 that aresolder interconnects, and DTPS interconnects 150-4 that are non-solderinterconnects (e.g., plated interconnects).

FIG. 23A illustrates an assembly 326 subsequent to forming the packagesubstrate portion 148 on the assembly 312 (FIG. 18A). The packagesubstrate portion 148 may be formed using any suitable techniques, suchas any of the techniques discussed above with reference to the formationof the package substrate portion 115 of FIG. 19G. In some embodiments,forming the package substrate portion 148 may include plating theconductive contacts 122 of the die 114-1 with a metal or otherconductive material as part of forming the proximate conductive contacts146 of the package substrate 102; consequently, the DTPS interconnects150-4 between the die 114-1 and the package substrate portion 148 may beplated interconnects.

FIG. 23B illustrates an assembly 328 subsequent to attaching the dies114-2, 114-3, and 114-4 to the assembly 326 (FIG. 23A). Any suitabletechniques may be used to form the DTPS interconnects 150 between thedies 114-2, 114-3, and 114-4 and the package substrate 102, such assolder techniques or anisotropic conductive material techniques.

FIGS. 24A-24E are side, cross-sectional views of various stages in anexample process for manufacturing the microelectronic assembly 100 ofFIG. 21, in accordance with various embodiments. In some embodiments,microelectronic assemblies 100 manufactured in accordance with theprocess of FIGS. 24A-24E may have DTPS interconnects 150-1 that aresolder interconnects, and DTPS interconnects 150-4 that are non-solderinterconnects (e.g., plated interconnects).

FIG. 24A illustrates an assembly 330 including the package substrateportion 153. The package substrate portion 153 may be manufactured usingany suitable technique, such as a PCB technique or a redistributionlayer technique.

FIG. 24B illustrates an assembly 332 subsequent to forming conductivepillars 134 on the top surface of the package substrate portion 153 ofthe assembly 330 (FIG. 24A). The conductive pillars 134 may be disposedaround a de-population region 155 in which no conductive pillars 134 arepresent. The conductive pillars 134 may take the form of any of theembodiments disclosed herein, and may be formed using any suitabletechnique (e.g., plating). For example, the conductive pillars 134 mayinclude copper.

FIG. 24C illustrates an assembly 334 subsequent to placing the die 114-1in the de-population region 155 of the assembly 332 (FIG. 24B) andcoupling the die 114-1 to the package substrate portion 153. Inparticular, the conductive contacts 122 at the bottom surface of the die114-1 may be coupled to the conductive contacts 146 at the top surfaceof the package substrate portion 153 via DTPS interconnects 150-1. TheDTPS interconnects 150-1 may take any of the forms disclosed herein,such as solder interconnects or anisotropic conductive materialinterconnects.

FIG. 24D illustrates an assembly 336 subsequent to providing a moldmaterial 132 around the die 114-1 and the conductive pillars 134 of theassembly 334 (FIG. 24C) to complete the package substrate portion 151.In some embodiments, the mold material 132 may be initially deposited onand over the tops of the conductive pillars 134 and the die 114-1, thenpolished back to expose the conductive contacts 122 at the top surfaceof the die 114-1, and the top surfaces of the conductive pillars 134.

FIG. 24E illustrates an assembly 338 subsequent to forming the packagesubstrate portion 148 on the assembly 336 (FIG. 24D). The packagesubstrate portion 148 may be formed using any suitable techniques, suchas any of the techniques discussed above with reference to the formationof the package substrate portion 115 of FIG. 19G. In some embodiments,forming the package substrate portion 148 may include plating theconductive contacts 122 of the die 114-1 with a metal or otherconductive material as part of forming the proximate conductive contacts146 of the package substrate 102; consequently, the DTPS interconnects150-4 between the die 114-1 and the package substrate portion 148 may beplated interconnects. The dies 114-2, 114-3, and 114-4 may then beattached to the top surface of the package substrate portion 148 inaccordance with any of the techniques discussed above with reference toFIG. 23B to form the microelectronic assembly 100 of FIG. 21.

FIGS. 25A-25F are side, cross-sectional views of various stages in anexample process for manufacturing the microelectronic assembly 100 ofFIG. 22, in accordance with various embodiments. In some embodiments,microelectronic assemblies 100 manufactured in accordance with theprocess of FIGS. 25A-25F may have DTPS interconnects 150-1 that arenon-solder interconnects (e.g., plated interconnects), and DTPSinterconnects 150-4 that are non-solder interconnects (e.g., platedinterconnects).

FIG. 25A illustrates an assembly 340 subsequent to forming a pluralityof conductive pillars 134 and a placement ring 136 on a carrier 202. Theconductive pillars 134 may take any of the forms disclosed herein, andmay be formed using any suitable technique (e.g., the techniquesdiscussed above with reference to FIG. 24B). The placement ring 136 maytake any of the forms disclosed herein, and may be formed using anysuitable technique (e.g., any of the techniques disclosed herein). Theplacement ring 136 may surround a de-population region 155 in which noconductive pillars 134 are present.

FIG. 25B illustrates an assembly 342 subsequent to positioning the die114-1 in the de-population region 155 within the placement ring 136 ofthe assembly 340 (FIG. 25A). As noted above, the placement ring 136 maycomplement the footprint of the die 114-1, allowing the die 114-1 to beproperly positioned.

FIG. 25C illustrates an assembly 344 subsequent to providing a moldmaterial 132 around the conductive pillars 134 and placement ring 136 ofthe assembly 342 (FIG. 25B) to complete the package substrate portion151. In some embodiments, the mold material 132 may be initiallydeposited on and over the tops of the conductive pillars 134 and the die114-1, then polished back to expose the conductive contacts 122 at thesurface of the die 114-1 and the surfaces of the conductive pillars 134.

FIG. 25D illustrates an assembly 346 subsequent to forming the packagesubstrate portion 153 on the assembly 344 (FIG. 25C). The packagesubstrate portion 153 may be formed using any suitable techniques, suchas any of the techniques discussed above with reference to the formationof the package substrate portion 115 of FIG. 19G. In some embodiments,forming the package substrate portion 153 may include plating theconductive contacts 122 of the die 114-1 with a metal or otherconductive material as part of forming the proximate conductive contacts146 of the package substrate 102; consequently, the DTPS interconnects150-1 between the die 114-1 and the package substrate portion 148 may beplated interconnects.

FIG. 25E illustrates an assembly 347 subsequent to attaching anothercarrier 204 to the top surface of the assembly 346 (FIG. 25D). Thecarrier 204 may take the form of any of the embodiments of the carrier202 disclosed herein.

FIG. 25F illustrates an assembly 348 subsequent to removing the carrier202 from the assembly 347 (FIG. 25E) and flipping the result so that thepackage substrate portion 151 and the other conductive contacts 122 ofthe die 114-1 are exposed. The package substrate portion 148 may then beformed on the assembly 348 in accordance with any of the techniquesdiscussed above with reference to FIG. 24E, and the dies 114-2, 114-3,and 114-4 may be attached to the top surface of the package substrateportion 148 (e.g., in accordance with any of the techniques discussedabove with reference to FIG. 23B) to form the microelectronic assembly100 of FIG. 21.

In any of the embodiments disclosed herein, a portion of the packagesubstrate 102 may be formed by assembling two separately manufacturedsub-portions. For example, FIGS. 26A-26D are side, cross-sectional viewsof various stages in another example process for manufacturing themicroelectronic assembly 100 of FIG. 21, in accordance with variousembodiments. The process of FIGS. 26A-26D includes the assembly of thepackage substrate portion 153 from two sub-portions, but any packagesubstrate 102 (or portion thereof) may be formed from multiplesub-portions.

FIG. 26A illustrates an assembly 350 subsequent to forming a packagesubstrate sub-portion 153A and forming conductive pillars 134 thereon.The conductive pillars 134 may take the form of any of the embodimentsdisclosed herein, and the package substrate sub-portion 153A mayrepresent the top half of the package substrate portion 153, asdiscussed further below.

FIG. 26B illustrates an assembly 352 subsequent to attaching a die 114-1to the assembly 350 (FIG. 26A), providing a mold material 132 around theconductive pillars 134 and the die 114-1 to complete the packagesubstrate portion 151, and forming a package substrate portion 148 onthe package substrate portion 151. These operations may take any of theforms discussed above.

FIG. 26C illustrates an assembly 354 subsequent to bringing the assembly352 (FIG. 26B) into alignment with a package substrate sub-portion 153B.In particular, the package substrate sub-portion 153A may be broughtproximate to the package substrate sub-portion 153B.

FIG. 26D illustrates an assembly 356 subsequent to coupling the packagesubstrate sub-portion 153A and the package substrate sub-portion 153B ofthe assembly 354 (FIG. 26C) together to form the package substrateportion 153. The dies 114-2, 114-3, and 114-4 may be attached to the topsurface of the package substrate portion 148 (e.g., in accordance withany of the techniques discussed above with reference to FIG. 23B, suchas solder or anisotropic conductive material techniques) to form themicroelectronic assembly 100 of FIG. 21.

The microelectronic assemblies 100 disclosed herein may includeconductive pillars 134 in the package substrate 102 even when the die114-1 is not embedded in the package substrate 102 (e.g., even when nopackage substrate portion 148 is present). For example, FIG. 27illustrates an example microelectronic assembly 100 in which the packagesubstrate 102 includes conductive pillars 134 without a packagesubstrate portion 148. In the microelectronic assembly 100 of FIG. 27,the conductive contacts 122 at the bottom surface of the die 114-2 arecoupled to the conductive pillars 134 via DTPS interconnects 150-2, andthe conductive contacts 124 at the bottom surface of the die 114-2 arecoupled to the conductive contacts 122 at the top surface of the die114-1 via DTD interconnects 130-2. Any of the other microelectronicassemblies 100 disclosed herein may include conductive pillars 134, asappropriate.

The microelectronic assemblies 100 disclosed herein may be used for anysuitable application. For example, in some embodiments, amicroelectronic assembly 100 may be used to provide an ultra-highdensity and high bandwidth interconnect for field programmable gatearray (FPGA) transceivers and III-V amplifiers. For example, the die114-1 may include FPGA transceiver circuitry or III-V amplifiers, andthe die 114-2 may include FPGA logic. Communications between the die114-1 and the die 114-2 may experience less delay than if suchcommunications were routed through an intermediate device (e.g., aseparate silicon bridge). In some embodiments, the pitch of the DTDinterconnects 130-1 between the die 114-1 and the die 114-2 may be lessthan 100 microns (e.g., between 25 microns and 55 microns) and the pitchof the DTPS interconnects 150-2 between the die 114-2 and the packagesubstrate 102 may be greater than 80 microns (e.g., between 100 micronsand 150 microns). Such applications may be particularly suitable formilitary electronics, 5G wireless communications, WiGig communications,and/or millimeter wave communications.

More generally, the microelectronic assemblies 100 disclosed herein mayallow “blocks” of different kinds of functional circuits to bedistributed into different ones of the dies 114, instead of having allof the circuits included in a single large die, per some conventionalapproaches. In some such conventional approaches, a single large diewould include all of these different circuits to achieve high bandwidth,low loss communication between the circuits, and some or all of thesecircuits may be selectively disabled to adjust the capabilities of thelarge die. However, because the DTD interconnects 130 of themicroelectronic assemblies 100 may allow high bandwidth, low losscommunication between different ones of the dies 114, different circuitsmay be distributed into different dies 114, reducing the total cost ofmanufacture, improving yield, and increasing design flexibility byallowing different dies 114 (e.g., dies 114 formed using differentfabrication technologies) to be readily swapped to achieve differentfunctionality. Additionally, a die 114 stacked on top of another die 114may be closer to the heat spreader 131 than if the circuitry of the twodies were combined into a single die farther from the heat spreader 131,improving thermal performance.

In another example, a die 114-1 that includes active circuitry in amicroelectronic assembly 100 may be used to provide an “active” bridgebetween other dies 114 (e.g., between the dies 114-2 and 114-3, orbetween multiple different dies 114-2, in various embodiments). In somesuch embodiments, power delivery may be provided to the “bottoms” of thedie 114-1 and the other dies 114 through the package substrate 102without requiring additional layers of package substrate 102 above thedie 140-1 through which to route power.

In another example, the die 114-1 in a microelectronic assembly 100 maybe a processing device (e.g., a central processing unit, a graphicsprocessing unit, a FPGA, a modem, an applications processor, etc.), andthe die 114-2 may include high bandwidth memory, transceiver circuitry,and/or input/output circuitry (e.g., Double Data Rate transfercircuitry, Peripheral Component Interconnect Express circuitry, etc.).In some embodiments, the die 114-1 may include a set of conductivecontacts 124 to interface with a high bandwidth memory die 114-2, adifferent set of conductive contacts 124 to interface with aninput/output circuitry die 114-2, etc. The particular high bandwidthmemory die 114-2, input/output circuitry die 114-2, etc. may be selectedfor the application at hand.

In another example, the die 114-1 in a microelectronic assembly 100 maybe a cache memory (e.g., a third level cache memory), and one or moredies 114-2 may be processing devices (e.g., a central processing unit, agraphics processing unit, a FPGA, a modem, an applications processor,etc.) that share the cache memory of the die 114-1.

As noted above, in various embodiments, the dies 114 included in amicroelectronic assembly 100 may be packaged or unpackaged dies.Examples of packaged dies may include wafer level chip scale packages,chip scale packages, embedded wafer level ball grid array packages, andball grid array packages, among others. Further, in some embodiments,one or more of the dies 114 included in a microelectronic assembly 100may be composite dies; a composite die itself may be a microelectronicassembly 100. As used herein, a “composite die” may refer to an assemblyof multiple packaged or unpackaged dies that can be treated as amonolithic unit when coupling the composite die to a package substrate102, another die 114, etc. Further, various ones of the microelectronicassemblies 100 disclosed herein may be formed by first assemblingdifferent ones of the dies 114 into a composite die, and then performingfurther assembly operations with the composite die (e.g., as discussedabove with reference to FIG. 17).

FIGS. 28-30 are side, cross-sectional views of example composite dies600, in accordance with various embodiments. For example, FIG. 28illustrates a composite die 600 including a die 614-1 and the die 614-2.The die 614-1 may be a double-sided die, and may take the form of any ofthe dies 114-1 disclosed herein. As illustrated in FIG. 28, the die614-1 may have conductive contacts 620 at its bottom surface (which maybe conductive contacts 122 or conductive contacts 124, as discussed infurther detail below), and the die 614-1 may have conductive contacts124 at its top surface. The conductive contacts 124 at the top surfaceof the die 614-1 may be coupled to conductive contacts 124 at the bottomsurface of the die 614-2 by DTD interconnects 130. In the embodiment ofFIG. 28, the die 614-2 may be a single-sided die as shown, and may takethe form of any of the single-sided dies disclosed herein. The DTDinterconnects 130 may take the form of any of the DTD interconnects 130disclosed herein.

In some embodiments, the die 614-1 in a composite die 600 may be“entirely under” the die 614-2; that is, the footprint of the die 614-1may be entirely contained in, and may be smaller than, the footprint ofthe die 614-2. An example of such an arrangement as illustrated in FIG.28, and other examples are illustrated in FIGS. 29-36. In someembodiments, the dimensions of the footprint of the die 614-1 may bestrictly smaller than the corresponding dimensions of the footprint ofthe die 614-2.

The bottom surface of the die 614-2 may include conductive contacts towhich the die 614-1 is not coupled. For example, FIG. 28 illustrates anembodiment in which the die 614-2 includes conductive contacts 620 atits bottom surface (which may be conductive contacts 122 or conductivecontacts 124, as discussed in further detail below). The conductivecontacts 620 of the dies 114 included in a composite die 600 may serveas the “outward facing” conductive contacts for the composite die 600(e.g., the conductive contacts to which other components, such as apackage substrate 102 or other dies 114, may couple). In the embodimentof FIG. 28, the die 614-1 also includes such conductive contacts 620.Different subsets of the conductive contacts 620 of a composite die 600may have different pitches; for example, the conductive contacts 620 atthe bottom surface of the die 614-1 may have a different pitch than theconductive contacts 620 at the bottom surface of the die 614-2, and/ordifferent subsets of the conductive contacts 620 at the bottom surfaceof the die 614-2 may have different pitches. In some embodiments, thefootprint of the conductive contacts 620 of the die 614-2 may be outsideof and/or surround the footprint of the die 614-1 (e.g., as illustratedin FIG. 28). In some embodiments, the die 614-2 may include conductivepathways between the conductive contacts 124 and the conductive contacts620 at the bottom surface of the die 614-2; these conductive pathwaysmay serve to route some of the signals from the die 614-1 to the“periphery” of the die 614-2, and then to another component to which theconductive contact 620 of the die 614-2 is coupled (e.g., a packagesubstrate 102 or another die 114).

As noted above, only a subset of the accompanying figures are labeledwith reference numerals representing dimensions, but this is simply forclarity of illustration, and any of the microelectronic assemblies 100disclosed herein may have components having the dimensions discussedherein. In some embodiments, the die 614-1 may be substantially thinnerthan the die 614-2. For example, in some embodiments, the thickness 187of the die 614-1 may be between 10 microns and 100 microns (e.g.,between 10 microns and 30 microns), while the thickness 185 of the die614-2 may be between 10 microns and 780 microns (e.g., between 50microns and 750 microns, between 50 microns and 400 microns, or between50 microns and 300 microns). In such embodiments, the thicker die 614-2may thus provide mechanical stability to the thinner die 614-1, and thushandling the composite die 600 may reduce the risk of mechanical damageto the die 614-1 relative to assembly operations in which the die 614-1is handled independently.

In some embodiments, the conductive contacts 620 at the bottom surfaceof the die 614-2 may be metal posts (e.g., copper posts) that extendaway from the bottom surface of the die 614-2. Such an embodiment isillustrated in FIG. 28. In some embodiments, the conductive contacts 620at the bottom surface of the die 614-2 may have a height 181 (measuredfrom the bottom surface of the die 614-2) between 5 microns and 80microns (e.g., between 10 microns and 40 microns). In variousembodiments, the height 181 of the conductive contacts 620 at the bottomsurface of the die 614-2 may be greater than, equal to, or less than thedistance 189 between the bottom surface of the die 614-1 and the bottomsurface of the die 614-2.

In some embodiments, the conductive contacts 124 at the bottom surfaceof the die 614-2 may be metal posts (e.g., copper posts) that extendaway from the bottom surface of the die 614-2. Such an embodiment isillustrated in FIG. 28. In some embodiments, the conductive contacts 124at the bottom surface of the die 614-2 may have a height 183 (measuredfrom the bottom surface of the die 614-2) between 1 micron and 10microns (e.g., 5 microns). The height 183 may be less than the height181, in some embodiments.

In some embodiments, multiple dies 614-1 may be coupled to a die 614-2in a composite die 600. For example, FIG. 29 illustrates an embodimentof a composite die 600 in which two dies 614-1 are coupled to a bottomsurface of the die 614-2. The composite die 600 of FIG. 29 also includesconductive contacts 620 at the bottom surfaces of the dies 614-1, andconductive contacts 620 at the bottom surface of the die 614-2; the dies614-1, the die 614-2, and the conductive contact 620 of these dies 614may take any of the forms discussed above. Although the composite die600 of FIG. 29 includes two dies 614-1, a composite die 600 may includeany number of dies 614-1 (e.g., 3, 4, or more dies 614-1).

In some embodiments, the die 614-2 in a composite die 600 may be adouble-sided die, and thus the composite die 600 may be a double-sideddie. For example, FIG. 30 illustrates a composite die 600 that issimilar to the composite die 600 of FIG. 28, but in which the die 614-2has conductive contacts 124 at its top surface, and is thus adouble-sided die. The die 614-2 of FIG. 30 may take the form of any ofthe double-sided dies disclosed herein, and a double-sided composite die600 may be used in the place of any of the double-sided dies disclosedherein (e.g., the dies 114-1).

As noted above, the conductive contacts 620 of a composite die 600 maybe coupled to a package substrate 102, a die 114, and/or any othercomponent. FIGS. 31-34 are side, cross-sectional views of examplemicroelectronic assemblies 100 including example composite dies 600, inaccordance with various embodiments. FIG. 31 illustrates amicroelectronic assembly 100 in which the composite die 600 of FIG. 28is coupled to a package substrate 102. In particular, the conductivecontacts 620 of the composite die 600 (on the bottom surfaces of the die614-1 and the die 614-2) may be coupled to conductive contacts 146 atthe top surface of the package substrate 102 by DTPS interconnects 150.Thus, in the embodiment of FIG. 31, the conductive contacts 620 of thecomposite die 600 may serve as conductive contacts 122 (the conductivecontacts on the die side of a set of DTPS interconnects 150).

FIG. 32 illustrates a microelectronic assembly 100 similar to themicroelectronic assembly 100 of FIG. 3, but in which the composite die600 of FIG. 29 takes the place of the die 114-2 of FIG. 3. Inparticular, some of the conductive contacts 620 of the composite die 600of FIG. 32 are coupled to conductive contacts 146 of the packagesubstrate by DTPS interconnects 150-2, and others of the conductivecontacts 620 of the composite die 600 of FIG. 32 are coupled toconductive contacts 124 of the die 114-1 by DTD interconnects 130-1. Asillustrated in FIG. 32, the conductive contacts 620-1 of one of the dies614-1 and the die 614-2 may be coupled to the conductive contacts 124 ofthe die 114-1 by DTD interconnects 130-1, and the conductive contacts620-2 of the dies 614-1 and the die 614-2 may be coupled to theconductive contacts 146 of the package substrate 102 by DTPSinterconnects 150-2. Thus, some of the conductive contacts 620 of thecomposite die 600 may serve as conductive contacts 122 (the conductivecontacts on the die side of a set of DTPS interconnects 150-2) and someof the conductive contact 620 of the composite die 600 may serve asconductive contacts 124 (the conductive contacts on one side of a set ofDTD interconnects 130-1). FIG. 32 is thus an example of an embodiment inwhich a composite die 600 may be directly coupled to both the packagesubstrate 102 and a die 114-1; more generally, a composite die 600 maytake the place of any of the dies 114-2 (or any of the other dies 114,such as the dies 114-1) disclosed herein.

FIG. 33 illustrates a microelectronic assembly 100 similar to themicroelectronic assembly 100 of FIG. 6, but in which the composite die600 of FIG. 30 takes the place of the die 114-7 of FIG. 6. As wasdiscussed above with reference to FIG. 32, in the embodiment of FIG. 33,the conductive contacts 620-1 of one of the dies 614-1 and the die 614-2may be coupled to the conductive contacts 124 of the die 114-1 by DTDinterconnects 130-1, and the conductive contacts 620-2 of the dies 614-1and the die 614-2 may be coupled to the conductive contacts 146 of thepackage substrate 102 by DTPS interconnects 150-2. Additionally, a die114-7 may have conductive contacts 124 at its bottom surface; theseconductive contacts 124 may be coupled to conductive contacts 124 at thetop surface of the die 614-2 by DTD interconnects 130-3. More generally,as noted above, a double-sided composite die 600 may be used in theplace of any of the double-sided dies 114 disclosed herein.

FIG. 34 illustrates a microelectronic assembly 100 similar to themicroelectronic assembly 100 of FIG. 32, but in which a single-sided die114-12 is disposed in the recess 108 and bridges the composite die 600and another die 114-2. The single-sided die 114-12 may be referred to asan “embedded bridge,” and may not have conductive contacts at its bottomsurface. In the embodiment of FIG. 34, the conductive contacts 620-1 ofone of the die 614-1 and the die 614-2 may be coupled to some of theconductive contacts 124 of the die 114-12 by DTD interconnects 130-1,and the conductive contacts 620-2 of the die 614-1 and the die 614-2 maybe coupled to conductive contacts 146 of the package substrate 102 byDTPS interconnects 150-2. Additionally, conductive contacts 124 at thebottom surface of the die 114-2 may be coupled to others of theconductive contacts 124 of the die 114-12 by DTD interconnects 130-2,and conductive contacts 122 at the bottom surface of the die 114-2 maybe coupled to conductive contacts 146 of the package substrate 102 byDTPS interconnects 150-1. The “embedded bridge” die 114-12 may provideconductive pathways through which the composite die 600 and the die114-2 may communicate.

As noted above, in some composite dies 600, the distance 189 from thebottom surface of the dies 614-2 to the bottom surface of the die 614-1may be greater than the height 181 of the conductive contacts 620 of thedie 614-2. For example, FIG. 35 is a side, cross-sectional view of anexample of such a composite die 600, in accordance with variousembodiments, and FIG. 36 is a side, cross-sectional view of an examplemicroelectronic assembly 100 including the composite die 600 of FIG. 35,in accordance with various embodiments. In the microelectronic assembly100 of FIG. 36, the die 614-1 may extend into a recess 108 in thepackage substrate 102. In the embodiment of FIG. 36, like the embodimentof FIG. 31, the conductive contacts 620 of the composite die 600 mayserve as conductive contacts 122 (the conductive contacts on the dieside of a set of DTPS interconnects 150).

Any suitable techniques may be used to manufacture the composite die 600(and related microelectronic assemblies 100) disclosed herein. Forexample, FIGS. 37A-37E are side, cross-sectional views of various stagesin an example process for manufacturing the microelectronic assembly 100of FIG. 31, in accordance with various embodiments. In some embodiments,only the operations of FIGS. 37A-37C may be performed to form thecomposite die 600. In some embodiments, operations like those discussedbelow with reference to FIG. 37B may be performed to couple thecomposite die 600 to another die (e.g., a die 114). In some embodiments,operations like those discussed below with reference to FIG. 37D or FIG.37E may be performed to couple the composite die 600 to a packagesubstrate (e.g., a package substrate 102).

FIG. 37A illustrates an assembly 360 including a carrier 202 and a die614-2 disposed on the carrier 202. The carrier 202 may take the form ofany of the carriers disclosed herein. The die 614-2 may be arranged“upside down” on the carrier 202 so that the conductive contacts 124 andthe conductive contacts 620 of the die 614-2 are exposed. In someembodiments, the die 614-2 of the assembly 360 may not be disposed on acarrier 202, but may instead be included in a wafer (not shown) thatincludes multiple copies of the die 614-2. In embodiments in which thedie 614-2 is disposed on a carrier 202 in the assembly 360, the die614-2 may have been singulated from other dies 614-2 in a wafer beforeinclusion in the assembly 360. In some such embodiments, the die 614-2may be overmolded on the carrier 202 (e.g., with a mold material 127,not shown), and the mold material may be polished back to expose theconductive contacts 620 and the conductive contacts 124 of the die614-2; further metal may then be deposited on the conductive contacts620 as needed to achieve a desired height (the height 181, not shown).As noted above, in some embodiments, the die 614-2 may be a packaged die(e.g., a wafer level chip scale package, a chip scale package, anembedded wafer level ball grid array package, a ball grid array package,etc.).

FIG. 37B illustrates an assembly 362 subsequent to coupling the die614-1 to the die 614-2 of the assembly 360 (FIG. 37A). In someembodiments, the die 614-1 may be secured to a carrier 204 for improvedhandling while it is coupled to the die 614-2. The interconnects 130between the die 614-1 and the die 614-2 may take any of the formsdisclosed herein (e.g., metal-to-metal bonding, anisotropic conductivematerial interconnects, solder interconnects, etc.). In embodiments inwhich the die 614-2 of the assembly 360 is part of a wafer of multipleones of the dies 614-2, the die 614-1 may be attached to the die 614-2in a die-to-wafer bonding operation. In embodiments in which the die614-2 is singulated from a wafer before the die 614-1 is attached, thedie 614-1 may be attached to the die 614-2 in a die-to-die bondingoperation. In some embodiments, a carrier 204 may not be used.

FIG. 37C illustrates an assembly 364 subsequent to removing the carrier204 from the assembly 362 (FIG. 37B). In some embodiments, the carrier204 may have been secured to the die 614-1 using a layer of releasematerial whose adhesion may be reduced by the provision of laser energy,thermal energy, chemical energy, etc. In some embodiments, a moldmaterial (e.g., the mold material 127 discussed above) may be providedon the assembly 364 (not shown) and then polished back to expose theconductive contacts 620. The dies 614-1 and 614-2 in the assembly 364may form a composite die 600.

FIG. 37D illustrates an assembly 366 subsequent to forming interconnects150 between the composite die 600 of the assembly 366 (FIG. 37D) and apackage substrate 102, and removing the carrier 202. The interconnects150 may be formed in accordance with any of the techniques disclosedherein (e.g., as discussed above with reference to FIGS. 17E and 17F),and the assembly 366 may take the form of the microelectronic assembly100 of FIG. 31. In some embodiments, the carrier 202 may be removed byactivating a release layer or by polishing the carrier 202 away. If thedie 114-2 was part of a wafer at the time die 114-1 was attached, thewafer (and any mold material) may be cut to singulate the dies 114-2before the composite die 600 is coupled to the package substrate 102

In some embodiments, the package substrate 102 of a microelectronicassembly 100 may be at least partially “built up” on a composite die600. For example, FIG. 37E illustrates an assembly 368 subsequent toforming the package substrate 102 on the composite die 600 (e.g., usingany of the techniques discussed above with reference to FIG. 19G or FIG.25D). In such embodiments, the interconnects 150 between the conductivecontacts 620 of the composite die 600 and the conductive contacts 146 ofthe package substrate 102 may be plated interconnects, as discussedabove.

The dies 614 included in a composite die 600 may include any suitablecircuitry. For example, in some embodiments, the dies 614-1 and 614-2may be central processing units or graphics processing units. In someembodiments, one or more of the dies 614-1 may be a central processingunit or a graphics processing unit, and the die 614-2 may be a memorydevice (e.g., a high bandwidth memory device). In some embodiments, oneor more of the dies 614-1 may be a memory device (e.g., a high bandwidthmemory device), and the die 614-2 may be a central processing unit or agraphics processing unit. In some embodiments, the DTD interconnects 130between the die 114-2 and the one or more dies 114-1 may provideconductive pathways for Double Data Rate channels through which the dies114-1 and 114-2 may communicate. In some embodiments, the composite die600 disclosed herein may be particularly suitable for applications inwhich low Z-height is desirable, such as mobile computing devices andtablet computing devices.

In some embodiments, the die 614-2 in a composite die 600 may includepower delivery switches and/or radio frequency switches. In someembodiments, the die 614-2 may be an active radio frequency chip (e.g.,including a silicon die substrate or a III-V die substrate), and the die614-1 may include control logic. Such an arrangement may achieve highbandwidth with low radio frequency parasitics.

In some embodiments, the die 614-2 may be a radio frequency chip thatdoes not include any active devices, and may instead include onlypassive devices (e.g., capacitors or inductors) on a high resistivitysilicon, glass, or ceramic die substrate, while the die 614-1 includescontrol logic. Such an arrangement may also achieve low radio frequencyparasitics, and including the passive devices in the die 614-2 may freeup valuable space in the die 614-1 for other circuitry (or allow the die614-1 to be made smaller).

In some embodiments, the die 614-2 may be built on a differentsemiconductor system then the die 614-1. For example, in someembodiments, the die 614-1 may include a silicon or germanium diesubstrate, and the die 614-2 may include a III-V material die substrate(or vice versa).

In some embodiments in which multiple dies 614-1 are coupled to a die614-2 in a composite die 600 (e.g., as discussed above with reference toFIG. 29 and FIGS. 32-34), the die 614-2 may act as “superposer” havingconductive pathways through which the different dies 614-1 maycommunicate. When such a composite die 600 is coupled to a packagesubstrate, the power to each die 614-1 may be delivered directly to thedies 614-1 from the power planes of the package substrate 102, ratherthan going through the die 614-2 (which would incur losses and increasearea). High bandwidth communication between the dies 614-1 through thedie 614-2 (e.g., through the metallization stack 1619 of the dies 614-1,as discussed below with reference to FIG. 39, or through TSVs throughthe die substrate 1602, as discussed below with reference to FIG. 39, ofthe dies 614-1) may be achieved.

In some embodiments, the die 614-2 of a composite die 600 may includepower conversion circuitry. In some embodiments, the die 614-2 of thecomposite die 600 may include cache memory and may be used by the one ormore dies 614-1 of the composite die 600. In some embodiments, the die614-2 of a composite die 600 may include a central processing unit or agraphics processing unit, and the one or more dies 614-1 may includepower conversion circuitry and/or memory devices (e.g., nonvolatilememory, such as nonvolatile memory to store the state of the centralprocessing unit or graphics processing unit). In some embodiments, thedie 614-2 of the composite die 600 may include repeater circuitry toamplify signals communicated between different ones of the dies 614-1through the die 614-2.

The top surface of the die 614-2 may provide a desirably “flat” topsurface for the composite die 600, allowing simple thermal andmechanical techniques to be used to dissipate heat and mechanicallysecure the composite die 600 (e.g., integrated heat spreaders, thermalinterface material, etc.).

The microelectronic assemblies 100 disclosed herein may be included inany suitable electronic component. FIGS. 38-41 illustrate variousexamples of apparatuses that may include, or be included in, any of themicroelectronic assemblies 100 disclosed herein.

FIG. 38 is a top view of a wafer 1500 and dies 1502 that may be includedin any of the microelectronic assemblies 100 disclosed herein (e.g., asany suitable ones of the dies 114). The wafer 1500 may be composed ofsemiconductor material and may include one or more dies 1502 having ICstructures formed on a surface of the wafer 1500. Each of the dies 1502may be a repeating unit of a semiconductor product that includes anysuitable IC. After the fabrication of the semiconductor product iscomplete, the wafer 1500 may undergo a singulation process in which thedies 1502 are separated from one another to provide discrete “chips” ofthe semiconductor product. The die 1502 may be any of the dies 114disclosed herein. The die 1502 may include one or more transistors(e.g., some of the transistors 1640 of FIG. 39, discussed below),supporting circuitry to route electrical signals to the transistors,passive components (e.g., signal traces, resistors, capacitors, orinductors), and/or any other IC components. In some embodiments, thewafer 1500 or the die 1502 may include a memory device (e.g., a randomaccess memory (RAM) device, such as a static RAM (SRAM) device, amagnetic RAM (MRAM) device, a resistive RAM (RRAM) device, aconductive-bridging RAM (CBRAM) device, etc.), a logic device (e.g., anAND, OR, NAND, or NOR gate), or any other suitable circuit element.Multiple ones of these devices may be combined on a single die 1502. Forexample, a memory array formed by multiple memory devices may be formedon a same die 1502 as a processing device (e.g., the processing device1802 of FIG. 41) or other logic that is configured to store informationin the memory devices or execute instructions stored in the memoryarray. Various ones of the microelectronic assemblies 100 disclosedherein may be manufactured using a die-to-wafer assembly technique inwhich some dies 114 are attached to a wafer 1500 that includes others ofthe dies 114, and the wafer 1500 is subsequently singulated.

FIG. 39 is a cross-sectional side view of an IC device 1600 that may beincluded in any of the microelectronic assemblies 100 disclosed herein(e.g., in any of the dies 114). One or more of the IC devices 1600 maybe included in one or more dies 1502 (FIG. 38). The IC device 1600 maybe formed on a die substrate 1602 (e.g., the wafer 1500 of FIG. 38) andmay be included in a die (e.g., the die 1502 of FIG. 38). The diesubstrate 1602 may be a semiconductor substrate composed ofsemiconductor material systems including, for example, n-type or p-typematerials systems (or a combination of both). The die substrate 1602 mayinclude, for example, a crystalline substrate formed using a bulksilicon or a silicon-on-insulator (SOI) substructure. In someembodiments, the die substrate 1602 may be formed using alternativematerials, which may or may not be combined with silicon, that include,but are not limited to, germanium, indium antimonide, lead telluride,indium arsenide, indium phosphide, gallium arsenide, or galliumantimonide. Further materials classified as group II-VI, III-V, or IVmay also be used to form the die substrate 1602. Although a few examplesof materials from which the die substrate 1602 may be formed aredescribed here, any material that may serve as a foundation for an ICdevice 1600 may be used. The die substrate 1602 may be part of asingulated die (e.g., the dies 1502 of FIG. 38) or a wafer (e.g., thewafer 1500 of FIG. 38).

The IC device 1600 may include one or more device layers 1604 disposedon the die substrate 1602. The device layer 1604 may include features ofone or more transistors 1640 (e.g., metal oxide semiconductorfield-effect transistors (MOSFETs)) formed on the die substrate 1602.The device layer 1604 may include, for example, one or more sourceand/or drain (S/D) regions 1620, a gate 1622 to control current flow inthe transistors 1640 between the S/D regions 1620, and one or more S/Dcontacts 1624 to route electrical signals to/from the S/D regions 1620.The transistors 1640 may include additional features not depicted forthe sake of clarity, such as device isolation regions, gate contacts,and the like. The transistors 1640 are not limited to the type andconfiguration depicted in FIG. 39 and may include a wide variety ofother types and configurations such as, for example, planar transistors,non-planar transistors, or a combination of both. Non-planar transistorsmay include FinFET transistors, such as double-gate transistors ortri-gate transistors, and wrap-around or all-around gate transistors,such as nanoribbon and nanowire transistors.

Each transistor 1640 may include a gate 1622 formed of at least twolayers, a gate dielectric and a gate electrode. The gate dielectric mayinclude one layer or a stack of layers. The one or more layers mayinclude silicon oxide, silicon dioxide, silicon carbide, and/or a high-kdielectric material. The high-k dielectric material may include elementssuch as hafnium, silicon, oxygen, titanium, tantalum, lanthanum,aluminum, zirconium, barium, strontium, yttrium, lead, scandium,niobium, and zinc. Examples of high-k materials that may be used in thegate dielectric include, but are not limited to, hafnium oxide, hafniumsilicon oxide, lanthanum oxide, lanthanum aluminum oxide, zirconiumoxide, zirconium silicon oxide, tantalum oxide, titanium oxide, bariumstrontium titanium oxide, barium titanium oxide, strontium titaniumoxide, yttrium oxide, aluminum oxide, lead scandium tantalum oxide, andlead zinc niobate. In some embodiments, an annealing process may becarried out on the gate dielectric to improve its quality when a high-kmaterial is used.

The gate electrode may be formed on the gate dielectric and may includeat least one p-type work function metal or n-type work function metal,depending on whether the transistor 1640 is to be a p-type metal oxidesemiconductor (PMOS) or an n-type metal oxide semiconductor (NMOS)transistor. In some implementations, the gate electrode may consist of astack of two or more metal layers, where one or more metal layers arework function metal layers and at least one metal layer is a fill metallayer. Further metal layers may be included for other purposes, such asa barrier layer. For a PMOS transistor, metals that may be used for thegate electrode include, but are not limited to, ruthenium, palladium,platinum, cobalt, nickel, conductive metal oxides (e.g., rutheniumoxide), and any of the metals discussed below with reference to an NMOStransistor (e.g., for work function tuning). For an NMOS transistor,metals that may be used for the gate electrode include, but are notlimited to, hafnium, zirconium, titanium, tantalum, aluminum, alloys ofthese metals, carbides of these metals (e.g., hafnium carbide, zirconiumcarbide, titanium carbide, tantalum carbide, and aluminum carbide), andany of the metals discussed above with reference to a PMOS transistor(e.g., for work function tuning).

In some embodiments, when viewed as a cross-section of the transistor1640 along the source-channel-drain direction, the gate electrode mayconsist of a U-shaped structure that includes a bottom portionsubstantially parallel to the surface of the die substrate 1602 and twosidewall portions that are substantially perpendicular to the topsurface of the die substrate 1602. In other embodiments, at least one ofthe metal layers that form the gate electrode may simply be a planarlayer that is substantially parallel to the top surface of the diesubstrate 1602 and does not include sidewall portions substantiallyperpendicular to the top surface of the die substrate 1602. In otherembodiments, the gate electrode may consist of a combination of U-shapedstructures and planar, non-U-shaped structures. For example, the gateelectrode may consist of one or more U-shaped metal layers formed atopone or more planar, non-U-shaped layers.

In some embodiments, a pair of sidewall spacers may be formed onopposing sides of the gate stack to bracket the gate stack. The sidewallspacers may be formed from materials such as silicon nitride, siliconoxide, silicon carbide, silicon nitride doped with carbon, and siliconoxynitride. Processes for forming sidewall spacers are well known in theart and generally include deposition and etching process steps. In someembodiments, a plurality of spacer pairs may be used; for instance, twopairs, three pairs, or four pairs of sidewall spacers may be formed onopposing sides of the gate stack.

The S/D regions 1620 may be formed within the die substrate 1602adjacent to the gate 1622 of each transistor 1640. The S/D regions 1620may be formed using an implantation/diffusion process or anetching/deposition process, for example. In the former process, dopantssuch as boron, aluminum, antimony, phosphorous, or arsenic may beion-implanted into the die substrate 1602 to form the S/D regions 1620.An annealing process that activates the dopants and causes them todiffuse farther into the die substrate 1602 may follow theion-implantation process. In the latter process, the die substrate 1602may first be etched to form recesses at the locations of the S/D regions1620. An epitaxial deposition process may then be carried out to fillthe recesses with material that is used to fabricate the S/D regions1620. In some implementations, the S/D regions 1620 may be fabricatedusing a silicon alloy such as silicon germanium or silicon carbide. Insome embodiments, the epitaxially deposited silicon alloy may be dopedin situ with dopants such as boron, arsenic, or phosphorous. In someembodiments, the S/D regions 1620 may be formed using one or morealternate semiconductor materials such as germanium or a group III-Vmaterial or alloy. In further embodiments, one or more layers of metaland/or metal alloys may be used to form the S/D regions 1620.

Electrical signals, such as power and/or input/output (I/O) signals, maybe routed to and/or from the devices (e.g., transistors 1640) of thedevice layer 1604 through one or more interconnect layers disposed onthe device layer 1604 (illustrated in FIG. 39 as interconnect layers1606-1610). For example, electrically conductive features of the devicelayer 1604 (e.g., the gate 1622 and the S/D contacts 1624) may beelectrically coupled with the interconnect structures 1628 of theinterconnect layers 1606-1610. The one or more interconnect layers1606-1610 may form a metallization stack (also referred to as an “ILDstack”) 1619 of the IC device 1600.

The interconnect structures 1628 may be arranged within the interconnectlayers 1606-1610 to route electrical signals according to a wide varietyof designs; in particular, the arrangement is not limited to theparticular configuration of interconnect structures 1628 depicted inFIG. 39. Although a particular number of interconnect layers 1606-1610is depicted in FIG. 39, embodiments of the present disclosure include ICdevices having more or fewer interconnect layers than depicted.

In some embodiments, the interconnect structures 1628 may include lines1628 a and/or vias 1628 b filled with an electrically conductivematerial such as a metal. The lines 1628 a may be arranged to routeelectrical signals in a direction of a plane that is substantiallyparallel with a surface of the die substrate 1602 upon which the devicelayer 1604 is formed. For example, the lines 1628 a may route electricalsignals in a direction in and out of the page from the perspective ofFIG. 39. The vias 1628 b may be arranged to route electrical signals ina direction of a plane that is substantially perpendicular to thesurface of the die substrate 1602 upon which the device layer 1604 isformed. In some embodiments, the vias 1628 b may electrically couplelines 1628 a of different interconnect layers 1606-1610 together.

The interconnect layers 1606-1610 may include a dielectric material 1626disposed between the interconnect structures 1628, as shown in FIG. 39.In some embodiments, the dielectric material 1626 disposed between theinterconnect structures 1628 in different ones of the interconnectlayers 1606-1610 may have different compositions; in other embodiments,the composition of the dielectric material 1626 between differentinterconnect layers 1606-1610 may be the same.

A first interconnect layer 1606 (referred to as Metal 1 or “M1”) may beformed directly on the device layer 1604. In some embodiments, the firstinterconnect layer 1606 may include lines 1628 a and/or vias 1628 b, asshown. The lines 1628 a of the first interconnect layer 1606 may becoupled with contacts (e.g., the S/D contacts 1624) of the device layer1604.

A second interconnect layer 1608 (referred to as Metal 2 or “M2”) may beformed directly on the first interconnect layer 1606. In someembodiments, the second interconnect layer 1608 may include vias 1628 bto couple the lines 1628 a of the second interconnect layer 1608 withthe lines 1628 a of the first interconnect layer 1606. Although thelines 1628 a and the vias 1628 b are structurally delineated with a linewithin each interconnect layer (e.g., within the second interconnectlayer 1608) for the sake of clarity, the lines 1628 a and the vias 1628b may be structurally and/or materially contiguous (e.g., simultaneouslyfilled during a dual-damascene process) in some embodiments.

A third interconnect layer 1610 (referred to as Metal 3 or “M3”) (andadditional interconnect layers, as desired) may be formed in successionon the second interconnect layer 1608 according to similar techniquesand configurations described in connection with the second interconnectlayer 1608 or the first interconnect layer 1606. In some embodiments,the interconnect layers that are “higher up” in the metallization stack1619 in the IC device 1600 (i.e., farther away from the device layer1604) may be thicker.

The IC device 1600 may include a solder resist material 1634 (e.g.,polyimide or similar material) and one or more conductive contacts 1636formed on the interconnect layers 1606-1610. In FIG. 39, the conductivecontacts 1636 are illustrated as taking the form of bond pads. Theconductive contacts 1636 may be electrically coupled with theinterconnect structures 1628 and configured to route the electricalsignals of the transistor(s) 1640 to other external devices. Forexample, solder bonds may be formed on the one or more conductivecontacts 1636 to mechanically and/or electrically couple a chipincluding the IC device 1600 with another component (e.g., a circuitboard). The IC device 1600 may include additional or alternatestructures to route the electrical signals from the interconnect layers1606-1610; for example, the conductive contacts 1636 may include otheranalogous features (e.g., posts) that route the electrical signals toexternal components. The conductive contacts 1636 may serve as theconductive contacts 122 or 124, as appropriate.

In some embodiments in which the IC device 1600 is a double-sided die(e.g., like the die 114-1), the IC device 1600 may include anothermetallization stack (not shown) on the opposite side of the devicelayer(s) 1604. This metallization stack may include multipleinterconnect layers as discussed above with reference to theinterconnect layers 1606-1610, to provide conductive pathways (e.g.,including conductive lines and vias) between the device layer(s) 1604and additional conductive contacts (not shown) on the opposite side ofthe IC device 1600 from the conductive contacts 1636. These additionalconductive contacts may serve as the conductive contacts 122 or 124, asappropriate.

In other embodiments in which the IC device 1600 is a double-sided die(e.g., like the die 114-1), the IC device 1600 may include one or moreTSVs through the die substrate 1602; these TSVs may make contact withthe device layer(s) 1604, and may provide conductive pathways betweenthe device layer(s) 1604 and additional conductive contacts (not shown)on the opposite side of the IC device 1600 from the conductive contacts1636. These additional conductive contacts may serve as the conductivecontacts 122 or 124, as appropriate.

FIG. 40 is a cross-sectional side view of an IC device assembly 1700that may include any of the microelectronic assemblies 100 disclosedherein. In some embodiments, the IC device assembly 1700 may be amicroelectronic assembly 100. The IC device assembly 1700 includes anumber of components disposed on a circuit board 1702 (which may be,e.g., a motherboard). The IC device assembly 1700 includes componentsdisposed on a first face 1740 of the circuit board 1702 and an opposingsecond face 1742 of the circuit board 1702; generally, components may bedisposed on one or both faces 1740 and 1742. Any of the IC packagesdiscussed below with reference to the IC device assembly 1700 may takethe form of any suitable ones of the embodiments of the microelectronicassemblies 100 disclosed herein.

In some embodiments, the circuit board 1702 may be a PCB includingmultiple metal layers separated from one another by layers of dielectricmaterial and interconnected by electrically conductive vias. Any one ormore of the metal layers may be formed in a desired circuit pattern toroute electrical signals (optionally in conjunction with other metallayers) between the components coupled to the circuit board 1702. Inother embodiments, the circuit board 1702 may be a non-PCB substrate. Insome embodiments the circuit board 1702 may be, for example, the circuitboard 133.

The IC device assembly 1700 illustrated in FIG. 40 includes apackage-on-interposer structure 1736 coupled to the first face 1740 ofthe circuit board 1702 by coupling components 1716. The couplingcomponents 1716 may electrically and mechanically couple thepackage-on-interposer structure 1736 to the circuit board 1702, and mayinclude solder balls (as shown in FIG. 40), male and female portions ofa socket, an adhesive, an underfill material, and/or any other suitableelectrical and/or mechanical coupling structure.

The package-on-interposer structure 1736 may include an IC package 1720coupled to an interposer 1704 by coupling components 1718. The couplingcomponents 1718 may take any suitable form for the application, such asthe forms discussed above with reference to the coupling components1716. Although a single IC package 1720 is shown in FIG. 40, multiple ICpackages may be coupled to the interposer 1704; indeed, additionalinterposers may be coupled to the interposer 1704. The interposer 1704may provide an intervening substrate used to bridge the circuit board1702 and the IC package 1720. The IC package 1720 may be, or mayinclude, for example, a die (the die 1502 of FIG. 38), an IC device(e.g., the IC device 1600 of FIG. 39), or any other suitable component.Generally, the interposer 1704 may spread a connection to a wider pitchor reroute a connection to a different connection. For example, theinterposer 1704 may couple the IC package 1720 (e.g., a die) to a set ofball grid array (BGA) conductive contacts of the coupling components1716 for coupling to the circuit board 1702. In the embodimentillustrated in FIG. 40, the IC package 1720 and the circuit board 1702are attached to opposing sides of the interposer 1704; in otherembodiments, the IC package 1720 and the circuit board 1702 may beattached to a same side of the interposer 1704. In some embodiments,three or more components may be interconnected by way of the interposer1704.

In some embodiments, the interposer 1704 may be formed as a PCB,including multiple metal layers separated from one another by layers ofdielectric material and interconnected by electrically conductive vias.In some embodiments, the interposer 1704 may be formed of an epoxyresin, a fiberglass-reinforced epoxy resin, an epoxy resin withinorganic fillers, a ceramic material, or a polymer material such aspolyimide. In some embodiments, the interposer 1704 may be formed ofalternate rigid or flexible materials that may include the samematerials described above for use in a semiconductor substrate, such assilicon, germanium, and other group III-V and group IV materials. Theinterposer 1704 may include metal interconnects 1708 and vias 1710,including but not limited to TSVs 1706. The interposer 1704 may furtherinclude embedded devices 1714, including both passive and activedevices. Such devices may include, but are not limited to, capacitors,decoupling capacitors, resistors, inductors, fuses, diodes,transformers, sensors, electrostatic discharge (ESD) devices, and memorydevices. More complex devices such as radio frequency devices, poweramplifiers, power management devices, antennas, arrays, sensors, andmicroelectromechanical systems (MEMS) devices may also be formed on theinterposer 1704. The package-on-interposer structure 1736 may take theform of any of the package-on-interposer structures known in the art.

The IC device assembly 1700 may include an IC package 1724 coupled tothe first face 1740 of the circuit board 1702 by coupling components1722. The coupling components 1722 may take the form of any of theembodiments discussed above with reference to the coupling components1716, and the IC package 1724 may take the form of any of theembodiments discussed above with reference to the IC package 1720.

The IC device assembly 1700 illustrated in FIG. 40 includes apackage-on-package structure 1734 coupled to the second face 1742 of thecircuit board 1702 by coupling components 1728. The package-on-packagestructure 1734 may include an IC package 1726 and an IC package 1732coupled together by coupling components 1730 such that the IC package1726 is disposed between the circuit board 1702 and the IC package 1732.The coupling components 1728 and 1730 may take the form of any of theembodiments of the coupling components 1716 discussed above, and the ICpackages 1726 and 1732 may take the form of any of the embodiments ofthe IC package 1720 discussed above. The package-on-package structure1734 may be configured in accordance with any of the package-on-packagestructures known in the art.

FIG. 41 is a block diagram of an example electrical device 1800 that mayinclude one or more of the microelectronic assemblies 100 disclosedherein. For example, any suitable ones of the components of theelectrical device 1800 may include one or more of the IC deviceassemblies 1700, IC devices 1600, or dies 1502 disclosed herein, and maybe arranged in any of the microelectronic assemblies 100 disclosedherein. A number of components are illustrated in FIG. 41 as included inthe electrical device 1800, but any one or more of these components maybe omitted or duplicated, as suitable for the application. In someembodiments, some or all of the components included in the electricaldevice 1800 may be attached to one or more motherboards. In someembodiments, some or all of these components are fabricated onto asingle system-on-a-chip (SoC) die.

Additionally, in various embodiments, the electrical device 1800 may notinclude one or more of the components illustrated in FIG. 41, but theelectrical device 1800 may include interface circuitry for coupling tothe one or more components. For example, the electrical device 1800 maynot include a display device 1806, but may include display deviceinterface circuitry (e.g., a connector and driver circuitry) to which adisplay device 1806 may be coupled. In another set of examples, theelectrical device 1800 may not include an audio input device 1824 or anaudio output device 1808, but may include audio input or output deviceinterface circuitry (e.g., connectors and supporting circuitry) to whichan audio input device 1824 or audio output device 1808 may be coupled.

The electrical device 1800 may include a processing device 1802 (e.g.,one or more processing devices). As used herein, the term “processingdevice” or “processor” may refer to any device or portion of a devicethat processes electronic data from registers and/or memory to transformthat electronic data into other electronic data that may be stored inregisters and/or memory. The processing device 1802 may include one ormore digital signal processors (DSPs), application-specific integratedcircuits (ASICs), central processing units (CPUs), graphics processingunits (GPUs), cryptoprocessors (specialized processors that executecryptographic algorithms within hardware), server processors, or anyother suitable processing devices. The electrical device 1800 mayinclude a memory 1804, which may itself include one or more memorydevices such as volatile memory (e.g., dynamic random access memory(DRAM)), nonvolatile memory (e.g., read-only memory (ROM)), flashmemory, solid state memory, and/or a hard drive. In some embodiments,the memory 1804 may include memory that shares a die with the processingdevice 1802. This memory may be used as cache memory and may includeembedded dynamic random access memory (eDRAM) or spin transfer torquemagnetic random access memory (STT-M RAM).

In some embodiments, the electrical device 1800 may include acommunication chip 1812 (e.g., one or more communication chips). Forexample, the communication chip 1812 may be configured for managingwireless communications for the transfer of data to and from theelectrical device 1800. The term “wireless” and its derivatives may beused to describe circuits, devices, systems, methods, techniques,communications channels, etc., that may communicate data through the useof modulated electromagnetic radiation through a nonsolid medium. Theterm does not imply that the associated devices do not contain anywires, although in some embodiments they might not.

The communication chip 1812 may implement any of a number of wirelessstandards or protocols, including but not limited to Institute forElectrical and Electronic Engineers (IEEE) standards including Wi-Fi(IEEE 802.11 family), IEEE 802.16 standards (e.g., IEEE 802.16-2005Amendment), Long-Term Evolution (LTE) project along with any amendments,updates, and/or revisions (e.g., advanced LTE project, ultra mobilebroadband (UMB) project (also referred to as “3GPP2”), etc.). IEEE802.16 compatible Broadband Wireless Access (BWA) networks are generallyreferred to as WiMAX networks, an acronym that stands for WorldwideInteroperability for Microwave Access, which is a certification mark forproducts that pass conformity and interoperability tests for the IEEE802.16 standards. The communication chip 1812 may operate in accordancewith a Global System for Mobile Communication (GSM), General PacketRadio Service (GPRS), Universal Mobile Telecommunications System (UMTS),High Speed Packet Access (HSPA), Evolved HSPA (E-HSPA), or LTE network.The communication chip 1812 may operate in accordance with Enhanced Datafor GSM Evolution (EDGE), GSM EDGE Radio Access Network (GERAN),Universal Terrestrial Radio Access Network (UTRAN), or Evolved UTRAN(E-UTRAN). The communication chip 1812 may operate in accordance withCode Division Multiple Access (CDMA), Time Division Multiple Access(TDMA), Digital Enhanced Cordless Telecommunications (DECT),Evolution-Data Optimized (EV-DO), and derivatives thereof, as well asany other wireless protocols that are designated as 3G, 4G, 5G, andbeyond. The communication chip 1812 may operate in accordance with otherwireless protocols in other embodiments. The electrical device 1800 mayinclude an antenna 1822 to facilitate wireless communications and/or toreceive other wireless communications (such as AM or FM radiotransmissions).

In some embodiments, the communication chip 1812 may manage wiredcommunications, such as electrical, optical, or any other suitablecommunication protocols (e.g., the Ethernet). As noted above, thecommunication chip 1812 may include multiple communication chips. Forinstance, a first communication chip 1812 may be dedicated toshorter-range wireless communications such as Wi-Fi or Bluetooth, and asecond communication chip 1812 may be dedicated to longer-range wirelesscommunications such as global positioning system (GPS), EDGE, GPRS,CDMA, WiMAX, LTE, EV-DO, or others. In some embodiments, a firstcommunication chip 1812 may be dedicated to wireless communications, anda second communication chip 1812 may be dedicated to wiredcommunications.

The electrical device 1800 may include battery/power circuitry 1814. Thebattery/power circuitry 1814 may include one or more energy storagedevices (e.g., batteries or capacitors) and/or circuitry for couplingcomponents of the electrical device 1800 to an energy source separatefrom the electrical device 1800 (e.g., AC line power).

The electrical device 1800 may include a display device 1806 (orcorresponding interface circuitry, as discussed above). The displaydevice 1806 may include any visual indicators, such as a heads-updisplay, a computer monitor, a projector, a touchscreen display, aliquid crystal display (LCD), a light-emitting diode display, or a flatpanel display.

The electrical device 1800 may include an audio output device 1808 (orcorresponding interface circuitry, as discussed above). The audio outputdevice 1808 may include any device that generates an audible indicator,such as speakers, headsets, or earbuds.

The electrical device 1800 may include an audio input device 1824 (orcorresponding interface circuitry, as discussed above). The audio inputdevice 1824 may include any device that generates a signalrepresentative of a sound, such as microphones, microphone arrays, ordigital instruments (e.g., instruments having a musical instrumentdigital interface (MIDI) output).

The electrical device 1800 may include a GPS device 1818 (orcorresponding interface circuitry, as discussed above). The GPS device1818 may be in communication with a satellite-based system and mayreceive a location of the electrical device 1800, as known in the art.

The electrical device 1800 may include an other output device 1810 (orcorresponding interface circuitry, as discussed above). Examples of theother output device 1810 may include an audio codec, a video codec, aprinter, a wired or wireless transmitter for providing information toother devices, or an additional storage device.

The electrical device 1800 may include an other input device 1820 (orcorresponding interface circuitry, as discussed above). Examples of theother input device 1820 may include an accelerometer, a gyroscope, acompass, an image capture device, a keyboard, a cursor control devicesuch as a mouse, a stylus, a touchpad, a bar code reader, a QuickResponse (QR) code reader, any sensor, or a radio frequencyidentification (RFID) reader.

The electrical device 1800 may have any desired form factor, such as ahand-held or mobile electrical device (e.g., a cell phone, a smartphone, a mobile internet device, a music player, a tablet computer, alaptop computer, a netbook computer, an ultrabook computer, a personaldigital assistant (PDA), an ultra mobile personal computer, etc.), adesktop electrical device, a server or other networked computingcomponent, a printer, a scanner, a monitor, a set-top box, anentertainment control unit, a vehicle control unit, a digital camera, adigital video recorder, or a wearable electrical device. In someembodiments, the electrical device 1800 may be any other electronicdevice that processes data.

The following paragraphs provide various examples of the embodimentsdisclosed herein.

Example 1 is a microelectronic assembly, including: a first die having afirst surface and an opposing second surface, first conductive contactsat the first surface of the first die, and second conductive contacts atthe second surface of the first die; and a second die having a firstsurface and an opposing second surface, first conductive contacts at thefirst surface of the second die, and second conductive contacts at thefirst surface of the second die; wherein the second conductive contactsof the first die are coupled to the first conductive contacts of thesecond die by interconnects, the second conductive contacts of thesecond die are not coupled to conductive contacts at the second surfaceof the first die, the second surface of the first die is between thefirst surface of the first die and the first surface of the second die,and a footprint of the first die is contained within a footprint of thesecond die.

Example 2 may include the subject matter of Example 1, and may furtherspecify that the first die has a thickness between 10 microns and 30microns.

Example 3 may include the subject matter of any of Examples 1-2, and mayfurther specify that the second die has a thickness between 50 micronsand 750 microns.

Example 4 may include the subject matter of any of Examples 1-3, and mayfurther specify that the second die has a thickness between 50 micronsand 400 microns.

Example 5 may include the subject matter of any of Examples 1-4, and mayfurther specify that the first conductive contacts of the second diehave a height that is less than a height of the second conductivecontacts of the second die.

Example 6 may include the subject matter of Example 5, and may furtherspecify that the first conductive contacts of the second die have aheight between 1 micron and 10 microns.

Example 7 may include the subject matter of any of Examples 5-6, and mayfurther specify that the second conductive contacts of the second diehave a height between 10 microns and 40 microns.

Example 8 may include the subject matter of any of Examples 5-7, and mayfurther specify that the first conductive contacts of the second die andthe second conductive contacts of the second die are metal posts.

Example 9 may include the subject matter of any of Examples 1-8, and mayfurther specify that the interconnects are metal-to-metal interconnects.

Example 10 may include the subject matter of any of Examples 1-8, andmay further specify that the interconnects are solder interconnects.

Example 11 may include the subject matter of any of Examples 1-8, andmay further specify that the interconnects include an anisotropicconductive material.

Example 12 may include the subject matter of any of Examples 1-11, andmay further specify that a distance from the first surface of the seconddie to the first surface of the first die is less that a height of thesecond conductive contacts of the second die.

Example 13 may include the subject matter of any of Examples 1-11, andmay further specify that a distance from the first surface of the seconddie to the first surface of the first die is more than a height of thesecond conductive contacts of the second die.

Example 14 may include the subject matter of any of Examples 1-13, andmay further specify that the interconnects are first interconnects, andthe microelectronic assembly further includes: a package substrate,wherein the first conductive contacts of the first die are coupled toconductive contacts of the package substrate with second interconnects,and the second conductive contacts of the second die are coupled toconductive contacts of the package substrate with third interconnects.

Example 15 may include the subject matter of Example 14, and may furtherspecify that the package substrate includes a recess, and the first dieis at least partially in the recess.

Example 16 may include the subject matter of any of Examples 14-15, andmay further specify that the package substrate includes an embeddedbridge, and at least some of the first conductive contacts of the firstdie or the second conductive contacts of the second die are coupled toconductive contacts of the embedded bridge.

Example 17 may include the subject matter of Example 16, and may furtherinclude: a third die having at least some conductive contacts coupled toconductive contacts of the embedded bridge by fourth interconnects.

Example 18 may include the subject matter of Example 17, and may furtherspecify that the third die is a field programmable gate array or a highbandwidth memory device.

Example 19 may include the subject matter of any of Examples 1-18, andmay further specify that the first die is one of a plurality of firstdies, individual ones of the first dies having a first surface and anopposing second surface, individual ones of the first dies having firstconductive contacts at the first surface of the first die, andindividual ones of the first dies having second conductive contacts atthe second surface of the first die, the second conductive contacts ofindividual ones of the first dies are coupled to the first conductivecontacts of the second die by interconnects, the second conductivecontacts of the second die are not coupled to conductive contacts at thesecond surface of the first dies, the second surfaces of individual onesof the first dies are between the first surfaces of individual ones ofthe first dies and the first surface of the second die, and footprint ofindividual ones of the first dies are contained within a footprint ofthe second die.

Example 20 may include the subject matter of Example 19, and may furtherspecify that the second die does not include active devices.

Example 21 may include the subject matter of Example 19, and may furtherspecify that the second die is a central processing unit or a graphicsprocessing unit.

Example 22 may include the subject matter of Example 19, and may furtherspecify that one or more of the first dies include a memory device orpower conversion circuitry.

Example 23 may include the subject matter of Example 19, and may furtherspecify that the second die includes amplification circuitry.

Example 24 may include the subject matter of any of Examples 1-23, andmay further specify that the first die is a central processing unit or agraphics processing unit, and the second die includes a memory device.

Example 25 may include the subject matter of any of Examples 1-24, andmay further specify that the first die includes a silicon die substrateand the second die includes a non-silicon die substrate.

Example 26 may include the subject matter of any of Examples 1-25, andmay further specify that the second die includes power delivery switchesor radio frequency switches.

Example 27 may include the subject matter of any of Examples 1-26, andmay further specify that the second die includes a III-V material.

Example 28 may include the subject matter of any of Examples 1-27, andmay further specify that the second die does not include active devices.

Example 29 may include the subject matter of Example 28, and may furtherspecify that the second die includes high resistivity silicon, glass, orceramic.

Example 30 may include the subject matter of any of Examples 28-29, andmay further specify that the second die includes capacitors orinductors.

Example 31 is a microelectronic assembly, including: a first die havinga first surface and an opposing second surface, first conductivecontacts at the first surface of the first die, and second conductivecontacts at the second surface of the first die; and a second die havinga first surface and an opposing second surface, and first conductivecontacts at the first surface of the second die; wherein the secondconductive contacts of the first die are coupled to the first conductivecontacts of the second die by interconnects, the second surface of thefirst die is between the first surface of the first die and the firstsurface of the second die, and a footprint of the first die is smallerthan and contained within a footprint of the second die.

Example 32 may include the subject matter of Example 31, and may furtherspecify that the first die has a thickness between 10 microns and 30microns.

Example 33 may include the subject matter of any of Examples 31-32, andmay further specify that the second die has a thickness between 50microns and 750 microns.

Example 34 may include the subject matter of any of Examples 31-33, andmay further specify that the second die has a thickness between 50microns and 400 microns.

Example 35 may include the subject matter of any of Examples 31-34, andmay further specify that the first conductive contacts of the second diehave a height that is less than a height of the second conductivecontacts of the second die.

Example 36 may include the subject matter of Example 35, and may furtherspecify that the first conductive contacts of the second die have aheight between 1 micron and 10 microns.

Example 37 may include the subject matter of any of Examples 35-36, andmay further specify that the second conductive contacts of the seconddie have a height between 10 microns and 40 microns.

Example 38 may include the subject matter of any of Examples 35-37, andmay further specify that the first conductive contacts of the second dieand the second conductive contacts of the second die are metal posts.

Example 39 may include the subject matter of any of Examples 31-38, andmay further specify that the interconnects are metal-to-metalinterconnects.

Example 40 may include the subject matter of any of Examples 31-38, andmay further specify that the interconnects are solder interconnects.

Example 41 may include the subject matter of any of Examples 31-38, andmay further specify that the interconnects include an anisotropicconductive material.

Example 42 may include the subject matter of any of Examples 31-41, andmay further specify that a distance from the first surface of the seconddie to the first surface of the first die is less that a height of thesecond conductive contacts of the second die.

Example 43 may include the subject matter of any of Examples 31-41, andmay further specify that a distance from the first surface of the seconddie to the first surface of the first die is more than a height of thesecond conductive contacts of the second die.

Example 44 may include the subject matter of any of Examples 31-43, andmay further specify that the interconnects are first interconnects, thesecond die further includes second conductive contacts at the firstsurface of the second die, and the microelectronic assembly furtherincludes: a package substrate, wherein the first conductive contacts ofthe first die are coupled to conductive contacts of the packagesubstrate with second interconnects, and the second conductive contactsof the second die are coupled to conductive contacts of the packagesubstrate with third interconnects.

Example 45 may include the subject matter of Example 44, and may furtherspecify that the package substrate includes a recess, and the first dieis at least partially in the recess.

Example 46 may include the subject matter of Example 44, and may furtherspecify that the package substrate includes an embedded bridge, and atleast some of the first conductive contacts of the first die or thesecond conductive contacts of the second die are coupled to conductivecontacts of the embedded bridge.

Example 47 may include the subject matter of Example 46, and may furtherinclude: a third die having at least some conductive contacts coupled toconductive contacts of the embedded bridge by fourth interconnects.

Example 48 may include the subject matter of Example 47, and may furtherspecify that the third die is a field programmable gate array or a highbandwidth memory device.

Example 49 may include the subject matter of any of Examples 31-48, andmay further specify that the first die is one of a plurality of firstdies, individual ones of the first dies having a first surface and anopposing second surface, individual ones of the first dies having firstconductive contacts at the first surface of the first die, andindividual ones of the first dies having second conductive contacts atthe second surface of the first die, the second conductive contacts ofindividual ones of the first dies are coupled to the first conductivecontacts of the second die by interconnects, the second conductivecontacts of the second die are not coupled to conductive contacts at thesecond surface of the first dies, the second surfaces of individual onesof the first dies are between the first surfaces of individual ones ofthe first dies and the first surface of the second die, and footprint ofindividual ones of the first dies are contained within a footprint ofthe second die.

Example 50 may include the subject matter of Example 49, and may furtherspecify that the second die does not include active devices.

Example 51 may include the subject matter of Example 49, and may furtherspecify that the second die is a central processing unit or a graphicsprocessing unit.

Example 52 may include the subject matter of Example 49, and may furtherspecify that one or more of the first dies include a memory device orpower conversion circuitry.

Example 53 may include the subject matter of Example 49, and may furtherspecify that the second die includes amplification circuitry.

Example 54 may include the subject matter of any of Examples 31-49, andmay further specify that the first die is a central processing unit or agraphics processing unit, and the second die includes a memory device.

Example 55 may include the subject matter of any of Examples 31-49, andmay further specify that the first die includes a silicon die substrateand the second die includes a non-silicon die substrate.

Example 56 may include the subject matter of any of Examples 31-49, andmay further specify that the second die includes power delivery switchesor radio frequency switches.

Example 57 may include the subject matter of any of Examples 31-49, andmay further specify that the second die includes a III-V material.

Example 58 may include the subject matter of any of Examples 31-49, andmay further specify that the second die does not include active devices.

Example 59 may include the subject matter of Example 58, and may furtherspecify that the second die includes high resistivity silicon, glass, orceramic.

Example 60 may include the subject matter of any of Examples 58-59, andmay further specify that the second die includes capacitors orinductors.

Example 61 is a method of manufacturing a microelectronic assembly,including: coupling a first surface of a first die to a carrier, whereinthe first die has the first surface and an opposing second surface, thefirst die has first conductive contacts are at the first surface of thefirst die, and the first die has second conductive contacts at thesecond surface of the first die; forming interconnects between thesecond conductive contacts of the first die and first conductivecontacts of a second die, wherein the second die has a first surface andan opposing second surface, the second die has first conductive contactsat the first surface of the second die, the second surface of the firstdie is between the first surface of the first die and the first surfaceof the second die, and a footprint of the first die is contained withina footprint of the second die; and after forming the interconnects,removing the carrier.

Example 62 may include the subject matter of Example 61, and may furtherspecify that the carrier is a first carrier, and the second die iscoupled to a second carrier when forming the interconnects.

Example 63 may include the subject matter of Example 62, and may furtherinclude: providing a mold material around the second die on the secondcarrier before forming the interconnects.

Example 64 may include the subject matter of Example 63, and may furtherinclude: after forming the interconnects, cutting the mold material.

Example 65 may include the subject matter of any of Examples 61-64, andmay further specify that the second die is one of a plurality of seconddies included in a wafer when forming the interconnects.

Example 66 may include the subject matter of any of Examples 61-64, andmay further specify that the second die is a packaged die when formingthe interconnects.

Example 67 may include the subject matter of any of Examples 61-64, andmay further specify that the second die is an unpackaged die whenforming the interconnects.

Example 68 may include the subject matter of any of Examples 61-67, andmay further specify that the interconnects are first interconnects, thesecond die further includes second conductive contacts at the firstsurface of the second die, and the method further includes: formingsecond interconnects between the first conductive contacts of the firstdie and conductive contacts of a package substrate; and forming thirdinterconnects between the second conductive contacts of the second dieand conductive contacts of a package substrate.

Example 69 may include the subject matter of any of Examples 61-68, andmay further specify that forming the interconnects includes performing ametal-to-metal bonding technique, a solder attach technique, or ananisotropic conductive material technique.

Example 70 may include the subject matter of any of Examples 61-69, andmay further include: after removing the carrier, forming aredistribution layer that includes conductive pathways in contact withthe first conductive contacts of the first die.

Example 71 is a computing device, including: a circuit board; and amicroelectronic package coupled to the circuit board, wherein themicroelectronic package includes: a first die having a first surface andan opposing second surface, first conductive contacts at the firstsurface of the first die, and second conductive contacts at the secondsurface of the first die; and a second die having a first surface and anopposing second surface, and first conductive contacts at the firstsurface of the second die, and wherein the second conductive contacts ofthe first die are coupled to the first conductive contacts of the seconddie by interconnects, the second surface of the first die is between thefirst surface of the first die and the first surface of the second die,and a footprint of the first die is smaller than and contained within afootprint of the second die.

Example 72 may include the subject matter of Example 71, and may furtherinclude: an antenna.

Example 73 may include the subject matter of any of Examples 71-72, andmay further specify that the computing device is a wearable computingdevice.

Example 74 may include the subject matter of any of Examples 71-72, andmay further specify that the computing device is a server.

Example 75 may include the subject matter of any of Examples 71-72, andmay further specify that the computing device is a mobile computingdevice.

Example 76 may include the subject matter of any of Examples 71-75, andmay further specify that the first die or the second die includes acentral processing unit or a graphics processing unit.

Example 77 may include the subject matter of any of Examples 71-76, andmay further include: a display.

1. A microelectronic assembly, comprising: a first die having a firstsurface and an opposing second surface, first conductive contacts at thefirst surface of the first die, and second conductive contacts at thesecond surface of the first die; and a second die having a first surfaceand an opposing second surface, first conductive contacts at the firstsurface of the second die, and second conductive contacts at the firstsurface of the second die; wherein the second conductive contacts of thefirst die are coupled to the first conductive contacts of the second dieby interconnects, the second conductive contacts of the second die arenot coupled to conductive contacts at the second surface of the firstdie, the second surface of the first die is between the first surface ofthe first die and the first surface of the second die, and a footprintof the first die is contained within a footprint of the second die. 2.The microelectronic assembly of claim 1, wherein the first die has athickness between 10 microns and 30 microns.
 3. The microelectronicassembly of claim 1, wherein the second die has a thickness between 50microns and 750 microns.
 4. The microelectronic assembly of claim 1,wherein the first die is a central processing unit or a graphicsprocessing unit, and the second die includes a memory device.
 5. Themicroelectronic assembly of claim 1, wherein the first die includes asilicon die substrate and the second die includes a non-silicon diesubstrate.
 6. The microelectronic assembly of claim 1, wherein thesecond die includes power delivery switches or radio frequency switches.7. The microelectronic assembly of claim 1, wherein the second dieincludes a III-V material.
 8. A microelectronic assembly, comprising: afirst die having a first surface and an opposing second surface, firstconductive contacts at the first surface of the first die, and secondconductive contacts at the second surface of the first die; and a seconddie having a first surface and an opposing second surface, and firstconductive contacts at the first surface of the second die; wherein thesecond conductive contacts of the first die are coupled to the firstconductive contacts of the second die by interconnects, the secondsurface of the first die is between the first surface of the first dieand the first surface of the second die, and a footprint of the firstdie is smaller than and contained within a footprint of the second die.9. The microelectronic assembly of claim 8, wherein the interconnectsare metal-to-metal interconnects.
 10. The microelectronic assembly ofclaim 8, wherein the interconnects include an anisotropic conductivematerial.
 11. The microelectronic assembly of claim 8, wherein adistance from the first surface of the second die to the first surfaceof the first die is less that a height of the second conductive contactsof the second die.
 12. The microelectronic assembly of claim 8, whereina distance from the first surface of the second die to the first surfaceof the first die is more than a height of the second conductive contactsof the second die.
 13. The microelectronic assembly of claim 8, whereinthe interconnects are first interconnects, the second die furtherincludes second conductive contacts at the first surface of the seconddie, and the microelectronic assembly further includes: a packagesubstrate, wherein the first conductive contacts of the first die arecoupled to conductive contacts of the package substrate with secondinterconnects, and the second conductive contacts of the second die arecoupled to conductive contacts of the package substrate with thirdinterconnects.
 14. The microelectronic assembly of claim 13, wherein thepackage substrate includes a recess, and the first die is at leastpartially in the recess.
 15. The microelectronic assembly of claim 13,wherein the package substrate includes an embedded bridge, and at leastsome of the first conductive contacts of the first die or the secondconductive contacts of the second die are coupled to conductive contactsof the embedded bridge.
 16. The microelectronic assembly of claim 15,further comprising: a third die having at least some conductive contactscoupled to conductive contacts of the embedded bridge by fourthinterconnects.
 17. A method of manufacturing a microelectronic assembly,comprising: coupling a first surface of a first die to a carrier,wherein the first die has the first surface and an opposing secondsurface, the first die has first conductive contacts are at the firstsurface of the first die, and the first die has second conductivecontacts at the second surface of the first die; forming interconnectsbetween the second conductive contacts of the first die and firstconductive contacts of a second die, wherein the second die has a firstsurface and an opposing second surface, the second die has firstconductive contacts at the first surface of the second die, the secondsurface of the first die is between the first surface of the first dieand the first surface of the second die, and a footprint of the firstdie is contained within a footprint of the second die; and after formingthe interconnects, removing the carrier.
 18. The method of claim 17,wherein the second die is one of a plurality of second dies included ina wafer when forming the interconnects.
 19. The method of claim 17,wherein the second die is a packaged die when forming the interconnects.20. The method of claim 17, wherein the second die is an unpackaged diewhen forming the interconnects.
 21. The method of claim 17, wherein theinterconnects are first interconnects, the second die further includessecond conductive contacts at the first surface of the second die, andthe method further includes: forming second interconnects between thefirst conductive contacts of the first die and conductive contacts of apackage substrate; and forming third interconnects between the secondconductive contacts of the second die and conductive contacts of apackage substrate.
 22. A computing device, comprising: a circuit board;and a microelectronic package coupled to the circuit board, wherein themicroelectronic package includes: a first die having a first surface andan opposing second surface, first conductive contacts at the firstsurface of the first die, and second conductive contacts at the secondsurface of the first die; and a second die having a first surface and anopposing second surface, and first conductive contacts at the firstsurface of the second die, and wherein the second conductive contacts ofthe first die are coupled to the first conductive contacts of the seconddie by interconnects, the second surface of the first die is between thefirst surface of the first die and the first surface of the second die,and a footprint of the first die is smaller than and contained within afootprint of the second die.
 23. The computing device of claim 22,wherein the computing device is a server.
 24. The computing device ofclaim 22, wherein the computing device is a mobile computing device. 25.The computing device of claim 22, wherein the first die or the seconddie includes a central processing unit or a graphics processing unit.